Leached superabrasive elements and systems, methods and assemblies for processing superabrasive materials

ABSTRACT

Superabrasive elements may be produced by method includes providing a superabrasive element including a polycrystalline diamond table that includes a metallic material disposed in interstitial spaces defined within the polycrystalline diamond table. The polycrystalline diamond table includes a superabrasive face and a superabrasive side surface extending around an outer periphery of the superabrasive face. The method also includes leaching the metallic material from at least a volume of the polycrystalline diamond table to produce a leached volume in the polycrystalline diamond table by (1) exposing at least a portion of the polycrystalline diamond table to a processing solution, (2) exposing an electrode to the processing solution, and (3) applying a charge to the electrode.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/020,751, titled “LEACHED SUPERABRASIVE ELEMENTS AND SYSTEMS, METHODSAND ASSEMBLIES FOR PROCESSING SUPERABRASIVE MATERIALS,” filed 27 Jun.2018, which application is a continuation of U.S. patent applicationSer. No. 14/864,152, titled “LEACHED SUPERABRASIVE ELEMENTS AND SYSTEMS,METHODS AND ASSEMBLIES FOR PROCESSING SUPERABRASIVE MATERIALS,” filed 24Sep. 2015, which claims the benefit of U.S. Provisional PatentApplication No. 62/062,553, titled “LEACHED SUPERABRASIVE ELEMENTS ANDSYSTEMS, METHODS AND ASSEMBLIES FOR PROCESSING SUPERABRASIVE MATERIALS,”filed 10 Oct. 2014, the disclosure of each of which is herebyincorporated by this reference in its entirety.

BACKGROUND

Wear-resistant, superabrasive materials are traditionally utilized for avariety of mechanical applications. For example, polycrystalline diamond(“PCD”) materials are often used in drilling tools (e.g., cuttingelements, gage trimmers, etc.), machining equipment, bearingapparatuses, wire-drawing machinery, and in other mechanical systems.Conventional superabrasive materials have found utility as superabrasivecutting elements in rotary drill bits, such as roller cone drill bitsand fixed-cutter drill bits. A conventional cutting element may includea superabrasive layer or table, such as a PCD table. The cutting elementmay be brazed, press-fit, or otherwise secured into a preformed pocket,socket, or other receptacle formed in the rotary drill bit. In anotherconfiguration, the substrate may be brazed or otherwise joined to anattachment member such as a stud or a cylindrical backing. Generally, arotary drill bit may include one or more PCD cutting elements affixed toa bit body of the rotary drill bit.

As mentioned above, conventional superabrasive materials have foundutility as bearing elements, which may include bearing elements utilizedin thrust bearing and radial bearing apparatuses. A conventional bearingelement typically includes a superabrasive layer or table, such as a PCDtable, bonded to a substrate. One or more bearing elements may bemounted to a bearing rotor or stator by press-fitting, brazing, orthrough other suitable methods of attachment. Typically, bearingelements mounted to a bearing rotor have superabrasive faces configuredto contact corresponding superabrasive faces of bearing elements mountedto an adjacent bearing stator.

Cutting elements having a PCD table may be formed and bonded to asubstrate using an ultra-high pressure, ultra-high temperature (“HPHT”)sintering process. Often, cutting elements having a PCD table arefabricated by placing a cemented carbide substrate, such as acobalt-cemented tungsten carbide substrate, into a container orcartridge with a volume of diamond particles positioned on a surface ofthe cemented carbide substrate. A number of such cartridges may beloaded into a HPHT press. The substrates and diamond particle volumesmay then be processed under HPHT conditions in the presence of acatalyst material that causes the diamond particles to bond to oneanother to form a diamond table having a matrix of bonded diamondcrystals. The catalyst material is often a metal-solvent catalyst, suchas cobalt, nickel, and/or iron, that facilitates intergrowth and bondingof the diamond crystals.

In one conventional approach, a constituent of the cemented-carbidesubstrate, such as cobalt from a cobalt-cemented tungsten carbidesubstrate, liquefies and sweeps from a region adjacent to the volume ofdiamond particles into interstitial regions between the diamondparticles during the HPHT process. The cobalt may act as a catalyst tofacilitate the formation of bonded diamond crystals. A metal-solventcatalyst may also be mixed with a volume of diamond particles prior tosubjecting the diamond particles and substrate to the HPHT process.

The metal-solvent catalyst may dissolve carbon from the diamondparticles and portions of the diamond particles that graphitize due tothe high temperatures used in the HPHT process. The solubility of thestable diamond phase in the metal-solvent catalyst may be lower thanthat of the metastable graphite phase under HPHT conditions. As a resultof the solubility difference, the graphite tends to dissolve into themetal-solvent catalyst and the diamond tends to deposit onto existingdiamond particles to form diamond-to-diamond bonds. Accordingly, diamondgrains may become mutually bonded to form a matrix of polycrystallinediamond, with interstitial regions defined between the bonded diamondgrains being occupied by the metal-solvent catalyst. In addition todissolving carbon and graphite, the metal-solvent catalyst may alsocarry tungsten, tungsten carbide, and/or other materials from thesubstrate into the PCD layer of the cutting element.

The presence of the metal-solvent catalyst and/or other materials in thediamond table may reduce the thermal stability of the diamond table atelevated temperatures. For example, the difference in thermal expansioncoefficient between the diamond grains and the solvent catalyst isbelieved to lead to chipping or cracking in the PCD table of a cuttingelement during drilling or cutting operations. The chipping or crackingin the PCD table may degrade the mechanical properties of the cuttingelement or lead to failure of the cutting element. Additionally, at hightemperatures, diamond grains may undergo a chemical breakdown orback-conversion with the metal-solvent catalyst. Further, portions ofdiamond grains may transform to carbon monoxide, carbon dioxide,graphite, or combinations thereof, thereby degrading the mechanicalproperties of the PCD material.

Accordingly, it is desirable to remove metallic materials, such asmetal-solvent catalysts, from a PCD material in situations where the PCDmaterial may be exposed to high temperatures. Chemical leaching is oftenused to dissolve and remove various materials from the PCD layer. Forexample, chemical leaching may be used to remove metal-solventcatalysts, such as cobalt, from regions of a PCD layer that mayexperience elevated temperatures during drilling, such as regionsadjacent to the working surfaces of the PCD layer.

During conventional leaching of a PCD table, exposed surface regions ofthe PCD table are immersed in a leaching solution until interstitialcomponents, such as a metal-solvent catalyst, are removed to a desireddepth from the exposed surface regions. The process of chemical leachingoften involves the use of highly concentrated and/or corrosivesolutions, such as aqua regia and mixtures including hydrofluoric acid(HF), to dissolve and remove metal-solvent catalysts frompolycrystalline diamond materials. Moreover, in addition to dissolvingmetal-solvent catalysts from a PCD material, leaching solutions may bedifficult to control, may take a long time, and may dissolve anyaccessible portions of a substrate to which the PCD material isattached. Therefore, improved methods for leaching PCD materials thatreduce or mitigate difficulties with conventional leaching are desired.

SUMMARY

The instant disclosure is directed to exemplary methods and assembliesfor processing superabrasive elements. In some examples, the method maycomprise exposing at least a portion of a polycrystalline diamondmaterial to a processing solution, exposing an electrode to theprocessing solution, applying a positive charge to the polycrystallinediamond material, and applying a negative charge to the electrode. Thepolycrystalline diamond material may comprise a metallic material (e.g.,cobalt, nickel, iron, and/or tungsten) disposed in interstitial spacesdefined within the polycrystalline diamond material.

The processing solution may comprise a suitable solution that leachesthe metallic material from interstitial spaces within at least a volumeof the polycrystalline diamond material. According to at least oneembodiment, the rate at which the processing solution leaches themetallic material from the interstitial spaces within at least thevolume of the polycrystalline diamond material is increased in thepresence of an electrical current between the polycrystalline diamondmaterial and the electrode. According to various embodiments, theelectrode may be disposed near at least the portion of thepolycrystalline diamond material. The electrode may be disposed suchthat the electrode does not directly contact the polycrystalline diamondmaterial.

The processing solution may at least partially oxidize the metallicmaterial when the polycrystalline diamond material is processed.According to at least one embodiment, the processing solution maycomprise an aqueous solution. According to some embodiments, theprocessing solution may comprise a buffered or a non-bufferedelectrolyte solution. In various embodiments, the processing solutionmay comprise at least one of acetic acid, ammonium chloride, arsenicacid, ascorbic acid, citric acid, formic acid, hydrobromic acid,hydrofluoric acid, hydroiodic acid, lactic acid, malic acid, nitricacid, oxalic acid, phosphoric acid, propionic acid, pyruvic acid,succinic acid, tartaric acid, and/or any suitable carboxylic acid (e.g.,monocarboxylic acid, polycarboxylic acid, etc.); the processing solutionmay additionally or alternatively comprise at least one of an ion, asalt, and an ester of at least one of the foregoing. The electrode maycomprise at least one of copper, tungsten carbide, cobalt, zinc, iron,platinum, palladium, niobium, graphite, graphene, nichrome, gold, andsilver. According to various embodiments, a masking layer may bedisposed over at least a portion of the polycrystalline diamondmaterial.

In some embodiments, a cation of the metallic material may be present inthe processing solution following application of the positive charge tothe polycrystalline diamond material and application of the negativecharge to the electrode. The cation of the metallic material may reducedand electrodeposited on the electrode. The processing solution maycomprise a first processing solution and the method may further compriseexposing at least the portion of the polycrystalline diamond material toa second processing solution (e.g., a more acidic solution than thefirst processing solution). At least a portion of the polycrystallinediamond material may be exposed to the second processing solutionfollowing exposure of at least the portion of the polycrystallinediamond material to the first processing solution. Additionally, atleast the portion of the polycrystalline diamond material may be exposedto the second processing solution prior to exposure of at least theportion of the polycrystalline diamond material to the first processingsolution. In some embodiments, an electrode for applying the positivecharge abuts the polycrystalline diamond material.

According to some embodiments, a method of processing a superabrasiveelement may include providing a superabrasive element, exposing at leasta portion of the superabrasive element to a processing solution,exposing an electrode to the processing solution, applying a firstcharge to the polycrystalline diamond table, and applying a secondcharge to the electrode. The polycrystalline diamond element maycomprise a substrate and a polycrystalline diamond table bonded to thesubstrate, the polycrystalline diamond table comprising a metallicmaterial disposed in interstitial spaces defined within thepolycrystalline diamond table. According to various embodiments, thefirst charge may be applied to the polycrystalline diamond table via thesubstrate. In some examples, a masking layer may be disposed over atleast a portion of the polycrystalline diamond table.

According to at least one embodiment, an assembly for processing apolycrystalline diamond body may include a volume of processingsolution, a polycrystalline diamond body, an electrode, and a powersource configured to apply a positive charge to the polycrystallinediamond body and a negative charge to the electrode. The polycrystallinediamond body and the electrode may both be in electrical communicationwith the processing solution. The polycrystalline diamond body maycomprise a metallic material disposed in interstitial spaces definedwithin the polycrystalline diamond body. At least a portion of thepolycrystalline diamond body and the electrode may be exposed to thevolume of processing solution. The assembly may additionally include afirst wire electrically connecting the power source to thepolycrystalline diamond body and a second wire electrically connectingthe power source to the electrode. The assembly may further include asubstrate bonded to the polycrystalline diamond body, the first wirebeing electrically connected to the substrate by an electrode disposedon a surface portion of the substrate.

Features from any of the disclosed embodiments may be used incombination with one another in accordance with the general principlesdescribed herein. These and other embodiments, features, and advantageswill be more fully understood upon reading the following detaileddescription in conjunction with the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate a number of exemplary embodimentsand are a part of the specification. Together with the followingdescription, these drawings demonstrate and explain various principlesof the instant disclosure.

FIG. 1 is a perspective view of an exemplary superabrasive elementaccording to at least one embodiment.

FIG. 2 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 3 is a perspective view of an exemplary superabrasive elementaccording to at least one embodiment.

FIG. 4 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 5 is a cross-sectional side view of a portion of a superabrasivetable according to at least one embodiment.

FIG. 6A is a magnified cross-sectional side view of a portion of asuperabrasive table according to at least one embodiment.

FIG. 6B is a magnified cross-sectional side view of a portion of asuperabrasive table according to at least one embodiment.

FIG. 7 is a perspective view of an exemplary superabrasive elementdisposed near an exemplary electrode according to at least oneembodiment.

FIG. 8 is a cross-sectional side view of an exemplary superabrasiveelement disposed near an exemplary electrode according to at least oneembodiment.

FIG. 9A is a cross-sectional side view of an exemplary superabrasiveelement disposed near an exemplary electrode and positioned within aprotective leaching cup according to at least one embodiment.

FIG. 9B is a cross-sectional side view of an exemplary superabrasiveelement disposed adjacent to an exemplary electrode and positionedwithin a protective leaching cup according to at least one embodiment.

FIG. 9C is a cross-sectional side view of an exemplary leaching assemblyaccording to at least one embodiment.

FIG. 10A is a cross-sectional side view of an exemplary leachingassembly according to at least one embodiment.

FIG. 10B is a cross-sectional side view of an exemplary leachedsuperabrasive element according to at least one embodiment.

FIG. 10C is a cross-sectional side view of an exemplary leachedsuperabrasive element according to at least one embodiment.

FIG. 10D is a cross-sectional side view of an exemplary leachingassembly according to at least one embodiment.

FIG. 10E is a cross-sectional side view of an exemplary leachingassembly according to at least one embodiment.

FIG. 11 is a perspective view of an exemplary superabrasive element andan exemplary electrode according to at least one embodiment.

FIG. 12 is a cross-sectional side view of an exemplary superabrasiveelement and an exemplary electrode according to at least one embodiment.

FIG. 13 is a perspective view of an exemplary superabrasive element andan exemplary electrode according to at least one embodiment.

FIG. 14 is a cross-sectional side view of an exemplary superabrasiveelement and an exemplary electrode according to at least one embodiment.

FIG. 15 is a cross-sectional side view of an exemplary superabrasiveelement and an exemplary electrode according to at least one embodiment.

FIG. 16 is a cross-sectional side view of an exemplary superabrasiveelement and an exemplary electrode according to at least one embodiment.

FIG. 17 is a cross-sectional side view of an exemplary superabrasiveelement and an exemplary electrode according to at least one embodiment.

FIG. 18 is a cross-sectional side view of an exemplary superabrasiveelement and an exemplary electrode according to at least one embodiment.

FIG. 19 is a cross-sectional side view of an exemplary superabrasiveelement and an exemplary electrode according to at least one embodiment.

FIG. 20 is a cross-sectional side view of an exemplary superabrasiveelement and an exemplary electrode according to at least one embodiment.

FIG. 21 is a cross-sectional side view of an exemplary superabrasiveelement and an exemplary electrode according to at least one embodiment.

FIG. 22 is a cross-sectional side view of an exemplary superabrasiveelement and exemplary electrodes according to at least one embodiment.

FIG. 23A is a perspective view of an exemplary superabrasive elementcoated with a masking layer and disposed near an exemplary electrodeaccording to at least one embodiment.

FIG. 23B is a cross-sectional side view of an exemplary superabrasiveelement coated with a masking layer and disposed near an exemplaryelectrode according to at least one embodiment.

FIG. 24 is a cross-sectional side view of an exemplary superabrasiveelement coated with a masking layer and disposed near an exemplaryelectrode according to at least one embodiment.

FIG. 25 is a cross-sectional side view of an exemplary superabrasiveelement coated with a masking layer and disposed near an exemplaryelectrode according to at least one embodiment.

FIG. 26 is a cross-sectional side view of an exemplary superabrasiveelement coated with a masking layer and disposed near an exemplaryelectrode according to at least one embodiment.

FIG. 27 is a cross-sectional side view of an exemplary superabrasiveelement coated with a masking layer and disposed near an exemplaryelectrode according to at least one embodiment.

FIG. 28 is a cross-sectional side view of an exemplary superabrasiveelement coated with a masking layer, positioned within a protectiveleaching cup, and disposed near an exemplary electrode according to atleast one embodiment.

FIG. 29 is a perspective view of an exemplary leaching assemblyaccording to at least one embodiment.

FIG. 30 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 31 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 32 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 33 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 34 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 35 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 36 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 37 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 38 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 39 is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 40A is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 40B is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 41A is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 41B is a cross-sectional side view of an exemplary superabrasiveelement according to at least one embodiment.

FIG. 42 is a perspective view of an exemplary drill bit according to atleast one embodiment.

FIG. 43 is a partial cut-away perspective view of an exemplary thrustbearing apparatus according to at least one embodiment.

FIG. 44 is a partial cut-away perspective view of an exemplary radialbearing apparatus according to at least one embodiment.

FIG. 45 is a partial cut-away perspective view of an exemplarysubterranean drilling system according to at least one embodiment.

FIG. 46 is a flow diagram of an exemplary method of processing apolycrystalline diamond element according to at least one embodiment.

FIG. 47 is a flow diagram of an exemplary method of processing apolycrystalline diamond element according to at least one embodiment.

Throughout the drawings, identical reference characters and descriptionsindicate similar, but not necessarily identical, elements. While theexemplary embodiments described herein are susceptible to variousmodifications and alternative forms, specific embodiments have beenshown by way of example in the drawings and will be described in detailherein. However, the exemplary embodiments described herein are notintended to be limited to the particular forms disclosed. Rather, theinstant disclosure covers all modifications, equivalents, andalternatives falling within the scope of the appended claims.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The instant disclosure is directed to exemplary leached superabrasiveelements and leaching systems, methods, and assemblies for processingsuperabrasive elements. Such superabrasive elements may be used ascutting elements for use in a variety of applications, such as drillingtools, machining equipment, cutting tools, and other apparatuses,without limitation. Superabrasive elements, as disclosed herein, mayalso be used as bearing elements in a variety of bearing applications,such as thrust bearings, radial bearings, and other bearing apparatuses,without limitation.

The terms “superabrasive” and “superhard,” as used herein, may refer toany material having a hardness that is at least equal to a hardness oftungsten carbide. For example, a superabrasive article may represent anarticle of manufacture, at least a portion of which may exhibit ahardness that is equal to or greater than the hardness of tungstencarbide. Additionally, the term “solvent,” as used herein, may refer toa single solvent compound, a mixture of two or more solvent compounds,and/or a mixture of one or more solvent compounds and one or moredissolved compounds. The term “molar concentration,” as used herein, mayrefer to a concentration in units of mol/L at a temperature ofapproximately 25° C. For example, a solution comprising solute A at amolar concentration of 1 M may comprise 1 mol of solute A per liter ofsolution. Moreover, the term “cutting,” as used herein, may refer tomachining processes, drilling processes, boring processes, and/or anyother material removal process utilizing a cutting element and/or othercutting apparatus, without limitation.

FIGS. 1 and 2 illustrate an exemplary superabrasive element 10 accordingto at least one embodiment. As illustrated in FIGS. 1 and 2,superabrasive element 10 may comprise a superabrasive table 14 affixedto or formed upon a substrate 12. Superabrasive table 14 may be affixedto substrate 12 at interface 26, which may be a planar or non-planarinterface. Superabrasive element 10 may comprise a rear surface 18, asuperabrasive face 20, and an element side surface 15. In someembodiments, element side surface 15 may include a substrate sidesurface 16 formed by substrate 12 and a superabrasive side surface 22formed by superabrasive table 14. Rear surface 18 may be formed bysubstrate 12.

Superabrasive element 10 may also comprise a chamfer 24 (i.e., sloped orangled) formed by superabrasive table 14. Chamfer 24 may comprise anangular and/or rounded edge formed at the intersection of superabrasiveside surface 22 and superabrasive face 20. Any other suitable surfaceshape may also be formed at the intersection of superabrasive sidesurface 22 and superabrasive face 20, including, without limitation, anarcuate surface (e.g., a radius, an ovoid shape, or any other roundedshape), a sharp edge, multiple chamfers/radii, a honed edge, and/orcombinations of the foregoing. At least one edge may be formed at theintersection of chamfer 24 and superabrasive face 20 and/or at theintersection of chamfer 24 and superabrasive side surface 22. Forexample, cutting element 10 may comprise one or more cutting edges, suchas an edge 27 and/or or an edge 28. Edge 27 and/or edge 28 may be formedadjacent to chamfer 24 and may be configured to be exposed to and/or incontact with a mining formation during drilling.

In some embodiments, superabrasive element 10 may be utilized as acutting element for a drill bit, in which chamfer 24 acts as a cuttingedge. The phrase “cutting edge” may refer, without limitation, to aportion of a cutting element that is configured to be exposed to and/orin contact with a subterranean formation during drilling. In at leastone embodiment, superabrasive element 10 may be utilized as a bearingelement (e.g., with superabrasive face 20 acting as a bearing surface)configured to contact oppositely facing bearing elements.

According to various embodiments, superabrasive element 10 may alsocomprise a substrate chamfer 13 formed by substrate 12. For example, achamfer comprising an angular and/or rounded edge may be formed bysubstrate 12 at the intersection of substrate side surface 16 and rearsurface 18. Any other suitable surface shape may also be formed at theintersection of substrate side surface 16 and rear surface 18,including, without limitation, an arcuate surface (e.g., a radius, anovoid shape, or any other rounded shape), a sharp edge, multiplechamfers/radii, a honed edge, and/or combinations of the foregoing.

Superabrasive element 10 may comprise any suitable size, shape, and/orgeometry, without limitation. According to at least one embodiment, atleast a portion of superabrasive element 10 may have a substantiallycylindrical shape. For example, superabrasive element 10 may comprise asubstantially cylindrical outer surface surrounding a central axis 29 ofsuperabrasive element 10, as illustrated in FIGS. 1 and 2. Substrateside surface 16 and superabrasive side surface 22 may, for example, besubstantially cylindrical and may have any suitable diameters relativeto central axis 29, without limitation. According to variousembodiments, substrate side surface 16 and superabrasive side surface 22may have substantially the same outer diameter relative to central axis29. Superabrasive element 10 may also comprise any other suitable shape,including, for example, an oval, ellipsoid, triangular, pyramidal,square, cubic, rectangular, and/or composite shape, and/or a combinationof the foregoing, without limitation.

According to various embodiments, superabrasive element 10 may alsocomprise a rear chamfer 19. For example, a rear chamfer 19 comprising anangular and/or rounded edge may be formed by superabrasive element 10 atthe intersection of substrate side surface 16 and rear surface 18. Anyother suitable surface shape may also be formed at the intersection ofsubstrate side surface 16 and rear surface 18, including, withoutlimitation, an arcuate surface (e.g., a radius, an ovoid shape, or anyother rounded shape), a sharp edge, multiple chamfers/radii, a honededge, and/or combinations of the foregoing.

Substrate 12 may comprise any suitable material on which superabrasivetable 14 may be formed. In at least one embodiment, substrate 12 maycomprise a cemented carbide material, such as a cobalt-cemented tungstencarbide material and/or any other suitable material. In someembodiments, substrate 12 may include a suitable metal-solvent catalystmaterial, such as, for example, cobalt, nickel, iron, and/or alloysthereof. Substrate 12 may also include any suitable material including,without limitation, cemented carbides such as titanium carbide, niobiumcarbide, tantalum carbide, vanadium carbide, chromium carbide, and/orcombinations of any of the preceding carbides cemented with iron,nickel, cobalt, and/or alloys thereof. Superabrasive table 14 may beformed of any suitable superabrasive and/or superhard material orcombination of materials, including, for example PCD. According toadditional embodiments, superabrasive table 14 may comprise cubic boronnitride, silicon carbide, polycrystalline diamond, and/or mixtures orcomposites including one or more of the foregoing materials, withoutlimitation.

Superabrasive table 14 may be formed using any suitable technique.According to some embodiments, superabrasive table 14 may comprise a PCDtable fabricated by subjecting a plurality of diamond particles to anHPHT sintering process in the presence of a metal-solvent catalyst(e.g., cobalt, nickel, iron, or alloys thereof) to facilitateintergrowth between the diamond particles and form a PCD body comprisedof bonded diamond grains that exhibit diamond-to-diamond bondingtherebetween. For example, the metal-solvent catalyst may be mixed withthe diamond particles, infiltrated from a metal-solvent catalyst foil orpowder adjacent to the diamond particles, infiltrated from ametal-solvent catalyst present in a cemented carbide substrate, orcombinations of the foregoing. The bonded diamond grains (e.g.,sp³-bonded diamond grains), so-formed by HPHT sintering the diamondparticles, define interstitial regions with the metal-solvent catalystdisposed within the interstitial regions of the as-sintered PCD body.The diamond particles may exhibit a selected diamond particle sizedistribution. Polycrystalline diamond elements, such as those disclosedin U.S. Pat. Nos. 7,866,418 and 8,297,382, the disclosure of each ofwhich is incorporated herein, in its entirety, by this reference, mayhave magnetic properties in at least some regions as disclosed thereinand leached regions in other regions as disclosed herein.

Following sintering, various materials, such as a metal-solventcatalyst, remaining in interstitial regions within the as-sintered PCDbody may reduce the thermal stability of superabrasive table 14 atelevated temperatures. In some examples, differences in thermalexpansion coefficients between diamond grains in the as-sintered PCDbody and a metal-solvent catalyst in interstitial regions between thediamond grains may weaken portions of superabrasive table 14 that areexposed to elevated temperatures, such as temperatures developed duringdrilling and/or cutting operations. The weakened portions ofsuperabrasive table 14 may be excessively worn and/or damaged during thedrilling and/or cutting operations.

Removing the metal-solvent catalyst and/or other materials from theas-sintered PCD body may improve the heat resistance and/or thermalstability of superabrasive table 14, particularly in situations wherethe PCD material may be exposed to elevated temperatures. Ametal-solvent catalyst and/or other materials may be removed from theas-sintered PCD body using any suitable technique, including, forexample, electrochemical leaching. In at least one embodiment, ametal-solvent catalyst, such as cobalt, may be removed from regions ofthe as-sintered PCD body, such as regions adjacent to the workingsurfaces of superabrasive table 14. Removing a metal-solvent catalystfrom the as-sintered PCD body may reduce damage to the PCD material ofsuperabrasive table 14 caused by expansion of the metal-solventcatalyst.

At least a portion of a metal-solvent catalyst, such as cobalt, as wellas other materials, may be removed from at least a portion of theas-sintered PCD body using any suitable technique, without limitation.For example, electrochemical, chemical and/or gaseous leaching may beused to remove a metal-solvent catalyst from the as-sintered PCD body upto a desired depth from a surface thereof. The as-sintered PCD body maybe electrochemically leached by immersion in an acid or acid solution,such as a solution including acetic acid, ammonium chloride, arsenicacid, ascorbic acid, citric acid, formic acid, hydrobromic acid,hydrofluoric acid, hydroiodic acid, lactic acid, malic acid, nitricacid, oxalic acid, phosphoric acid, propionic acid, pyruvic acid,succinic acid, tartaric acid, and/or any suitable carboxylic acid (e.g.,monocarboxylic acid, polycarboxylic acid, etc.), in the presence of anelectrode, such as copper, tungsten carbide, cobalt, zinc, iron,platinum, palladium, niobium, graphite, graphene, nichrome, gold, and/orsilver electrode, wherein a charge is applied to the as-sintered PCDbody and an opposite charge is applied to the electrode or subjected toanother suitable process to remove at least a portion of themetal-solvent catalyst from the interstitial regions of the PCD body andform superabrasive table 14 comprising a PCD table. For example, theas-sintered PCD body may be immersed in an acid solution in the presenceof an electrode, a positive charge may be applied to the as-sintered PCDbody and a negative charge may be applied to the electrode for aselected amount of time. For example, a PCD body may be positivelycharged and an electrode may be negatively charged for more than 4hours, more than 10 hours, between 24 hours to 48 hours, about 2 toabout 7 days (e.g., about 3, 5, or 7 days), for a few weeks (e.g., about4 weeks), or for 1-2 months, depending on the process employed.

Even after leaching, a residual, detectable amount of the metal-solventcatalyst may be present in the at least partially leached superabrasivetable 14. It is noted that when the metal-solvent catalyst isinfiltrated into the diamond particles from a cemented tungsten carbidesubstrate including tungsten carbide particles cemented with ametal-solvent catalyst (e.g., cobalt, nickel, iron, or alloys thereof),the infiltrated metal-solvent catalyst may carry tungsten and/ortungsten carbide therewith and the as-sintered PCD body may include suchtungsten and/or tungsten carbide therein disposed interstitially betweenthe bonded diamond grains. The tungsten and/or tungsten carbide may beat least partially removed by the selected leaching process or may berelatively unaffected by the selected leaching process.

In some embodiments, only selected portions of the as-sintered PCD bodymay be leached, leaving remaining portions of resulting superabrasivetable 14 unleached. For example, some portions of one or more surfacesof the as-sintered PCD body may be masked or otherwise protected fromexposure to a processing solution and/or gas mixture while otherportions of one or more surfaces of the as-sintered PCD body may beexposed to the processing solution and/or gas mixture. Other suitabletechniques may be used for removing a metal-solvent catalyst and/orother materials from the as-sintered PCD body or may be used toaccelerate an electrochemical leaching process, as will be described ingreater detail below. For example, exposing the as-sintered PCD body toheat, pressure, microwave radiation, and/or ultrasound may be employedto leach or to accelerate an electrochemical leaching process, withoutlimitation. Following leaching, superabrasive table 14 may comprise avolume of PCD material that is at least partially free or substantiallyfree of a metal-solvent catalyst.

The plurality of diamond particles used to form superabrasive table 14comprising the PCD material may exhibit one or more selected sizes. Theone or more selected sizes may be determined, for example, by passingthe diamond particles through one or more sizing sieves or by any othermethod. In an embodiment, the plurality of diamond particles may includea relatively larger size and at least one relatively smaller size. Asused herein, the phrases “relatively larger” and “relatively smaller”refer to particle sizes determined by any suitable method, which differby at least a factor of two (e.g., 40 μm and 20 μm). More particularly,in various embodiments, the plurality of diamond particles may include aportion exhibiting a relatively larger size (e.g., 100 μm, 90 μm, 80 μm,70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 15 μm, 12 μm, 10 μm, 8 μm) andanother portion exhibiting at least one relatively smaller size (e.g.,30 μm, 20 μm, 15 μm, 12 μm, 10 μm, 8 μm, 4 μm, 2 μm, 1 μm, 0.5 μm, lessthan 0.5 μm, 0.1 μm, less than 0.1 μm). In another embodiment, theplurality of diamond particles may include a portion exhibiting arelatively larger size between about 40 μm and about 15 μm and anotherportion exhibiting a relatively smaller size between about 12 μm and 2μm. Of course, the plurality of diamond particles may also include threeor more different sizes (e.g., one relatively larger size and two ormore relatively smaller sizes), without limitation. Different sizes ofdiamond particle may be disposed in different locations within apolycrystalline diamond volume, without limitation. According to atleast one embodiment, disposing different sizes of diamond particles indifferent locations may facilitate control of a leach depth, as will bedescribed in greater detail below.

FIGS. 3 and 4 illustrate an exemplary superabrasive element 110according to various embodiments. Superabrasive element 110 may comprisea superabrasive table 114 that is not attached to a substrate. As shownin FIGS. 3 and 4, superabrasive element 110 may include a rear surface118, a superabrasive face 120, and an element side surface 122 formed bysuperabrasive table 114. Superabrasive element 110 may also comprise achamfer 124 (i.e., sloped or angled) and/or any other suitable surfaceshape at the intersection of element side surface 122 and superabrasiveface 120, including, without limitation, an arcuate surface (e.g., aradius, an ovoid shape, or any other rounded shape), a sharp edge,multiple chamfers/radii, a honed edge, and/or combinations of theforegoing. At least one edge, such as an edge 127 and/or or an edge 128,may be formed at the intersection of chamfer 124 and each ofsuperabrasive face 120 and element side surface 122, respectively.Element side surface 122 of superabrasive element 110 may radiallysurround a central axis 129 of superabrasive element 110.

According to various embodiments, superabrasive element 110 may alsocomprise a rear chamfer 119. For example, a rear chamfer 119 comprisingan angular and/or rounded edge may be formed by superabrasive element110 at the intersection of element side surface 122 and rear surface118. Any other suitable surface shape may also be formed at theintersection of element side surface 122 and rear surface 118,including, without limitation, an arcuate surface (e.g., a radius, anovoid shape, or any other rounded shape), a sharp edge, multiplechamfers/radii, a honed edge, and/or combinations of the foregoing.

Superabrasive element 110 may be formed using any suitable technique,including, for example, HPHT sintering, as described above. In someexamples, superabrasive element 110 may be created by first forming asuperabrasive element 10 that includes a substrate 12 and asuperabrasive table 14, as detailed above in reference to FIGS. 1 and 2.Once superabrasive element 10 has been produced, superabrasive table 14may be separated from substrate 12 to form superabrasive element 110.For example, prior to or following leaching, superabrasive table 14 maybe separated from substrate 12 using any suitable process, including alapping process, a grinding process, a wire-electrical-dischargemachining (“wire EDM”) process, or any other suitable material-removalprocess, without limitation.

According to some embodiments, superabrasive element 110 may beprocessed and utilized either with or without an attached substrate. Forexample, following leaching, superabrasive element may be secureddirectly to a cutting tool, such as a drill bit, or to a bearingcomponent, such as a rotor or stator. In various embodiments, followingprocessing, superabrasive element 110 may be attached to a substrate.For example, rear surface 118 of superabrasive element 110 may bebrazed, welded, soldered, threadedly coupled, and/or otherwise adheredand/or fastened to a substrate, such as tungsten carbide substrate orany other suitable substrate, without limitation. Polycrystallinediamond elements having pre-sintered polycrystalline diamond bodiesincluding an infiltrant, such as those disclosed in U.S. Pat. No.8,323,367, the disclosure of which is incorporated herein, in itsentirety, by this reference, may be leached a second time according tothe processes disclosed herein after reattachment of the pre-sinteredpolycrystalline diamond bodies.

FIG. 5 is a cross-sectional side view of a portion of an exemplarysuperabrasive table 214, such as the superabrasive tables 14 and 114illustrated in FIGS. 1-4. Superabrasive table 14 may comprise acomposite material, such as a PCD material. A PCD material may include amatrix of bonded diamond grains and interstitial regions defined betweenthe bonded diamond grains. Such interstitial regions may be at leastpartially filled with various materials. In some embodiments, ametal-solvent catalyst may be disposed in interstitial regions insuperabrasive table 14. Tungsten and/or tungsten carbide may also bepresent in the interstitial regions.

According to various embodiments, materials may be deposited ininterstitial regions during processing of superabrasive table 14. Forexample, material components of substrate 12 may migrate into a mass ofdiamond particles used to form a superabrasive table 14 during HPHTsintering. As the mass of diamond particles is sintered, a metal-solventcatalyst may melt and flow from substrate 12 into the mass of diamondparticles. As the metal-solvent flows into superabrasive table 14, itmay dissolve and/or carry additional materials, such as tungsten and/ortungsten carbide, from substrate 12 into the mass of diamond particles.As the metal-solvent catalyst flows into the mass of diamond particles,the metal-solvent catalyst, and any dissolved and/or undissolvedmaterials, may at least partially fill spaces between the diamondparticles. The metal-solvent catalyst may facilitate bonding of adjacentdiamond particles to form a PCD layer. Following sintering, anymaterials, such as, for example, the metal-solvent catalyst, tungsten,and/or tungsten carbide, may remain in interstitial regions withinsuperabrasive table 14.

To improve the performance and heat resistance of a surface ofsuperabrasive table 14, at least a portion of a metal-solvent catalyst,such as cobalt, may be removed from at least a portion of superabrasivetable 14. Optionally, tungsten and/or tungsten carbide may be removedfrom at least a portion of superabrasive table 14. A metal-solventcatalyst, as well as other materials, may be removed from superabrasivetable 14 using any suitable technique, without limitation.

For example, electrochemical leaching may be used to remove ametal-solvent catalyst from superabrasive table 214 up to a depth D froma surface of superabrasive table 214, as illustrated in FIG. 5. As shownin FIG. 5, depth D may be measured relative to an external surface ofsuperabrasive table 214, such as superabrasive face 220, superabrasiveside surface 222, and/or chamfer 224. In some examples, a metal-solventcatalyst may be removed from superabrasive table 214 up to a depth D ofapproximately 2500 μm. In additional examples, a metal-solvent catalystmay be removed from superabrasive table 214 up to a depth D of betweenapproximately 100 and 1000 μm.

Following leaching, superabrasive table 214 may comprise a first volume221 and a second volume 223. Following leaching, superabrasive table 214may comprise, for example, a first volume 221 that contains ametal-solvent catalyst. An amount of metal-solvent catalyst in firstvolume 221 may be substantially the same prior to and followingleaching. In various embodiments, first volume 221 may be remote fromone or more exposed surfaces of superabrasive table 214.

Second volume 223 may comprise a volume of superabrasive table 214having a lower concentration of the interstitial material than firstvolume 221. For example, second volume 223 may be substantially free ofa metal-solvent catalyst. However, small amounts of catalyst may remainwithin interstices that are inaccessible to the leaching process. Secondvolume 223 may extend from one or more surfaces of superabrasive table214 (e.g., superabrasive face 220, superabrasive side surface 222,and/or chamfer 224) to a depth D from the one or more surfaces. Secondvolume 223 may be located adjacent one or more surfaces of superabrasivetable 214. An amount of metal-solvent catalyst in first volume 221and/or second volume 223 may vary at different depths in superabrasivetable 214.

In at least one embodiment, superabrasive table 214 may include atransition region 225 between first volume 221 and second volume 223.Transition region 225 may include amounts of metal-solvent catalystvarying between an amount of metal-solvent catalyst in first volume 221and an amount of metal-solvent catalyst in second volume 223. In variousexamples, transition region 225 may comprise a relatively narrow regionbetween first volume 221 and second volume 223.

FIGS. 6A and 6B are magnified cross-sectional side views of a portion ofthe superabrasive table 214 illustrated in FIG. 5 according to variousembodiments. As shown in FIGS. 6A and 6B, superabrasive table 214 maycomprise grains 234 and interstitial regions 236 between grains 234defined by grain surfaces 238. Grains 234 may comprise grains formed ofany suitable superabrasive material, including, for example, diamondgrains. At least some of grains 234 may be bonded to one or moreadjacent grains 234, forming a polycrystalline diamond matrix.

Interstitial material 239 may be disposed in at least some ofinterstitial regions 236. Interstitial material 239 may comprise anysuitable material, such as, for example, a metal-solvent catalyst,tungsten, and/or tungsten carbide. As shown in FIG. 6A, interstitialmaterial 239 may not be present in at least some of interstitial regions236. At least a portion of interstitial material 239 may be removed fromat least some of interstitial regions 236 during a leaching procedure.For example, a substantial portion of interstitial material 239 may beremoved from second volume 223 during a leaching procedure. Additionallyinterstitial material 239 may remain in a first volume 221 following aleaching procedure. In some embodiments, as shown in FIG. 6B, at leastsome of interstitial regions 236 may be partially filled withinterstitial material 231 that is not removed by leaching. For example,in one embodiment, cobalt may be substantially removed from at leastsome of interstitial regions 236 of first volume 221 and/or secondvolume 223, while tungsten and/or tungsten carbide may remain in the atleast some of interstitial regions 236 of first volume 221 and/or secondvolume 223.

In some examples, interstitial material 239 may be removed from table214 to a depth that improves the performance and/or heat resistance of asurface of superabrasive table 214 to a desired degree. In someembodiments, interstitial material 239 may be removed from superabrasivetable 214 to a practical limit. In order to remove interstitial material239 from superabrasive table 214 to a depth beyond the practical limit,for example, significantly more time, temperature, and/or other processparameter may be required. In some embodiments, interstitial material239 may be removed from superabrasive table 214 to a practical limit ordesired degree where interstitial material remains in at least a portionof superabrasive table 214. In various embodiments, superabrasive table214 may be fully leached so that interstitial material 239 issubstantially removed from a substantial portion of superabrasive table214.

In at least one embodiment, as will be described in greater detailbelow, interstitial material 239 may be leached from a superabrasivematerial, such as a PCD material in superabrasive table 214, by exposingthe superabrasive material to a suitable processing solution in thepresence of an electrode and applying a charge (e.g., a positive charge)to the superabrasive material and an opposite charge (e.g., a negativecharge) to the electrode. Interstitial material 239 may include ametal-solvent catalyst, such as cobalt, nickel, iron, and/or alloysthereof.

FIGS. 7-28 show exemplary configurations of superabrasive elements andelectrodes for leaching the superabrasive elements. The configurationsillustrated in these figures may enable selective leaching of portionsof the superabrasive elements to form desired leach profiles within thesuperabrasive elements. While certain configurations of superabrasiveelements are shown and described herein for purposes of illustration,the apparatuses and methods described herein may be applied to anysuperabrasive article having any suitable material, shape, andconfiguration, without limitation.

FIGS. 7 and 8 illustrate an exemplary superabrasive element 10 disposednear an exemplary electrode 40 according to at least one embodiment. Asillustrated in FIGS. 7 and 8, superabrasive element 10 may comprise asuperabrasive table 14 affixed to or formed upon a substrate 12.Superabrasive table 14 may be affixed to substrate 12 at interface 26,which may be a planar or non-planar interface. Superabrasive element 10may comprise a rear surface 18, a superabrasive face 20, and an elementside surface 15. In some embodiments, element side surface 15 mayinclude a substrate side surface 16 formed by substrate 12 and asuperabrasive side surface 22 formed by superabrasive table 14. Rearsurface 18 may be formed by substrate 12.

Superabrasive element 10 may also comprise a chamfer 24 (i.e., sloped orangled) formed by superabrasive table 14. Chamfer 24 may comprise anangular and/or rounded edge formed at the intersection of superabrasiveside surface 22 and superabrasive face 20. Any other suitable surfaceshape may also be formed at the intersection of superabrasive sidesurface 22 and superabrasive face 20, including, without limitation, anarcuate surface (e.g., a radius, an ovoid shape, or any other roundedshape), a sharp edge, multiple chamfers/radii, a honed edge, and/orcombinations of the foregoing.

Electrode 40 may comprise any suitable size, shape, and/or geometry,without limitation. According to at least one embodiment, at least aportion of electrode 40 may have a substantially cylindrical shape. Forexample, electrode 40 may comprise a substantially cylindrical outersurface surrounding a central axis of electrode 40, as illustrated inFIGS. 7 and 8. Electrode 40 may comprise any suitable material that mayconduct electricity. Electrode 40 may have an outer diameter that issubstantially the same as the outer diameter of element side surface 15of superabrasive element 10. In at least one embodiment, electrode 40may comprise copper. Electrode 40 may comprise any suitable electricallyconductive material, such as, for example, copper, tungsten carbide,cobalt, zinc, iron, platinum, palladium, niobium, graphite, graphene,nichrome, gold, silver, alloys thereof, any suitable metallic material,and/or any other suitable electrically conductive material, withoutlimitation.

According to various embodiments, a charge may be applied tosuperabrasive element 10 and electrode 40 through electrical conductors(e.g., wires or any suitable electrical conductor) 44 and 42,respectively. For example, in order to apply a current to processingsolution for processing superabrasive element 10, superabrasive element10 and electrical conductor 44 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge (e.g., a positive charge) may be applied to atleast a portion of substrate 12 (e.g., rear surface 18) of superabrasiveelement 10 through electrical conductor 44 and an opposite charge (e.g.,a negative charge) may be applied to electrode 40 through electricalconductor 42. In at least one embodiment, electrical conductor 44 may beelectrically connected to substrate 12 by an electrode electricallyconnected to (e.g., positioned abutting) substrate 12. In someembodiments, electrical conductor 44 may be directly connected tosuperabrasive table 14 by an electrode electrically connected to (e.g.,positioned abutting) superabrasive table 14.

When superabrasive element 10 is disposed in a processing solution suchthat at least a portion of superabrasive table 14 and electrode 40 areexposed to the processing solution when a voltage is applied to theprocessing solution via electrode 40 and superabrasive table 14,interstitial materials may be removed from at least a portion ofsuperabrasive table 14 of superabrasive element 10 near electrode 40.

FIGS. 9A and 9B illustrate an exemplary superabrasive element 10disposed near an exemplary electrode 40 and positioned within aprotective leaching cup 30 according to at least one embodiment. Asillustrated in FIGS. 9A and 9B, superabrasive element 10 may comprise asuperabrasive table 14 affixed to or formed upon a substrate 12.Superabrasive table 14 may be affixed to substrate 12 at interface 26,which may be a planar or non-planar interface. Superabrasive element 10may comprise a rear surface 18, a superabrasive face 20, and an elementside surface 15. In some embodiments, element side surface 15 mayinclude a substrate side surface 16 formed by substrate 12 and asuperabrasive side surface 22 formed by superabrasive table 14. Rearsurface 18 may be formed by substrate 12. Superabrasive element 10 mayalso comprise a chamfer 24 formed by superabrasive table 14. Chamfer 24may comprise an angular and/or rounded edge formed between superabrasiveside surface 22 and superabrasive face 20.

As shown in FIGS. 9A and 9B, superabrasive element 10 may be positionedwithin protective leaching cup 30 such that protective leaching cup 30surrounds at least a portion of superabrasive element 10, includingsubstrate 12. When superabrasive element 10 is positioned withinprotective leaching cup 30, at least a portion of superabrasive element10, such as superabrasive table 14 and/or substrate 12, may bepositioned adjacent to and/or contacting a portion of protectiveleaching cup 30. For example, protective leaching cup 30 may beconfigured to contact at least a portion of element side surface 15 ofsuperabrasive element 10, forming a seal between protective leaching cup30 and superabrasive element 10, where the leaching cup 30 is partiallyor fully impermeable to various fluids, such as a leaching material(e.g., a leaching solution).

Protective leaching cup 30 may be formed of any suitable material,without limitation. For example, protective leaching cup 30 may comprisea flexible, elastic, malleable, and/or otherwise deformable materialconfigured to surround and/or contact at least a portion ofsuperabrasive element 10. Protective leaching cup 30 may prevent damageto superabrasive element 10 when at least a portion of superabrasiveelement 10 is exposed to various reactive agents. For example,protective leaching cup 30 may prevent a leaching solution fromchemically damaging certain portions of superabrasive element 10, suchas portions of substrate 12, portions of superabrasive table 14, orboth, during leaching. Protective leaching cup 30 may be formed with anopening 32 configured to allow electrical conductor 44 to contract rearsurface 18 of superabrasive element 10. Optionally, opening 32 may besealed with a sealant (e.g., silicone, epoxy, etc.) to prevent theleaching solution from damaging substrate 12, if necessary.

In various embodiments, protective layer 30 may comprise one or morematerials that are substantially inert and/or otherwise resistant toacids, bases, and/or other reactive components present in a leachingsolution used to leach superabrasive element 10. In some embodiments,protective layer 30 may comprise one or more materials exhibitingsignificant stability at various temperatures and/or pressures,including selected temperatures and/or pressures used in leaching and/orotherwise processing superabrasive element 10. In some embodiments,protective leaching cup 30 may include one or more polymeric materials,such as, for example, nylon, polytetrafluoroethylene (PTFE),polyethylene, polypropylene, rubber, silicone, and/or other polymers,and/or a combination of any of the foregoing, without limitation. Forexample, protective leaching cup 30 may comprise PTFE blended with oneor more other polymeric materials.

Electrode 40 may be disposed near and/or abutting superabrasive element10. For example, as shown in FIG. 9A, electrode 40 may be disposed near,but separated from, superabrasive table 14 of superabrasive element 10.Electrode 40 may be disposed any suitable distance away fromsuperabrasive element 10. Optionally, as illustrated in FIG. 9B,electrode 40 may be disposed adjacent to at least a portion ofsuperabrasive element 10. For example, electrode 40 may be electricallyconnected to (e.g., positioned abutting) a portion of superabrasivetable 14, such as superabrasive face 20. Although not shown, electrode40 may be disposed adjacent to any other suitable portion ofsuperabrasive table 14, such as, for example, superabrasive side surface22 and/or chamfer 24.

FIG. 9C is a cross-sectional side view of an exemplary leaching assemblyaccording to at least one embodiment. As illustrated in FIG. 9C,superabrasive element 10 may be positioned within a protective leachingcup 30 and disposed near electrode 40. Superabrasive element 10,electrode 40, and protective leaching cup 30 may further be positionedwithin a processing vessel 70.

As shown in FIG. 9C, processing vessel 70 may have a rear wall 74 and aside wall 73 defining a cavity 76. Rear wall 74 and side wall 73 mayhave any suitable shape, without limitation. Processing vessel 70 mayinclude an opening 78 opposite rear wall 74. Cavity 76 may contain aprocessing solution 72 such that at least a portion of superabrasiveelement 10 is exposed to processing solution 72. Superabrasive element10 may be positioned in cavity 76 so that superabrasive element 10 ispositioned adjacent to or near rear wall 74 of processing vessel 70. Insome embodiments, superabrasive element 10 may be positioned and/orsecured within processing vessel 70 using any suitable mechanism,without limitation. Processing vessel 70 may be larger than leaching cup30, so that there are gaps between leaching cup 30 and processing vessel70. In other embodiments, more than one superabrasive element 10 andprotective leaching cup 30 (e.g., 10 or more, 20 or more, etc.) may beplaced within a single processing vessel 70 for loading.

According to some embodiments, processing solution 72 may comprise aconductive solution (e.g., a conductive aqueous solution, a conductivenon-aqueous solution, etc.). Solvents in such processing solution 72 maycomprise water and/or any other suitable solvent, without limitation.Processing solution 72 may also comprise dissolved electrolytes. Suchelectrolytes may comprise any suitable electrolyte compounds, including,without limitation, acetic acid, ammonium chloride, arsenic acid,ascorbic acid, citric acid, formic acid, hydrobromic acid, hydrofluoricacid, hydroiodic acid, lactic acid, malic acid, nitric acid, oxalicacid, phosphoric acid, propionic acid, pyruvic acid, succinic acid,tartaric acid, and/or any suitable carboxylic acid (e.g., monocarboxylicacid, polycarboxylic acid, etc.), and/or ions, salts, and/or esters ofany of the foregoing, and/or any combination of the foregoing. Suchelectrolytes may be present in processing solution 72 at any suitableconcentration, without limitation. For example, one or more electrolytesmay be present in processing solution 72 at a concentration of, forexample, less than approximately 5 M. In certain embodiments, one ormore electrolytes may be present in processing solution 72 at aconcentration of, for example, less than approximately 0.01 M. In atleast one embodiment, one or more electrolytes may be present inprocessing solution 72 at a concentration of, for example, betweenapproximately 0.01 M and approximately 3 M. In some embodiments, one ormore electrolytes may be present in processing solution 72 at aconcentration of, for example, between approximately 0.1 M andapproximately 1 M. In additional embodiments, one or more electrolytesmay be present in processing solution 72 at a concentration of, forexample, between approximately 0.2 M and approximately 0.4 M. In atleast one embodiment, one or more electrolytes may be present inprocessing solution 72 at a concentration of, for example, approximately0.3 M.

Processing solution 72 may have a pH of between approximately 1 andapproximately 12. In certain embodiments, processing solution 72 mayhave a pH below approximately 1. In some embodiments, processingsolution 72 may have a pH of between approximately 1 and approximately7. In at least one embodiment, for example, processing solution 72 mayhave a pH approximately 2.0.

In some embodiments, processing solution 72 may include metal salts,such as cobalt salts, iron salts, nickel salts, copper salts, and/or anyother suitable transition metal salts, and/or any other suitable metalion salts, without limitation. Such metal salts may include, forexample, cobalt chloride, cobalt nitrate, iron chloride, and/or anyother suitable metal salts, without limitation. One or more metal saltsmay be present in processing solution 72 at any suitable concentration,including, for example, a concentration of less than approximately 2 M.In at least one embodiment, one or more metal salts may be present inprocessing solution 72 at a concentration of, for example, betweenapproximately 0.01 M and approximately 1 M. In some embodiments, one ormore metal salts may be present in processing solution 72 at aconcentration of, for example, between approximately 0.03 M andapproximately 0.5 M. In additional embodiments, one or more metal saltsmay be present in processing solution 72 at a concentration of, forexample, between approximately 0.05 M and approximately 0.3 M. In atleast one embodiment, for example, one or more compounds may bedissolved in processing solution 72 at a concentration of, for example,approximately 0.1 M.

Processing solution 72 may further include any other suitablecomponents, without limitation, including, for example, a bufferingagent (e.g., boric acid, an amine compound such as ethylenediamine,triethanolamine, ethanolamine, etc.), a pH control agent (e.g., sodiumhydroxide, etc.), and/or a conducting agent (e.g., sodium sulfate,ammonium citrate, etc.). In some examples, processing solution 72 maycomprise an acid (e.g., a mineral acid) suitable for increasing thesolubility of a metallic material, such as cobalt or any other material,with respect to processing solution 72, including, for example, nitricacid, hydrochloric acid, phosphoric acid, sulfuric acid, boric acid,hydrofluoric acid, and/or any combination of the foregoing mineralacids. The acid may be selected for its ability to attack and/ordissolve a metallic material within superabrasive table 14. Processingsolution 72 may then carry the dissolved metallic material out ofsuperabrasive table 14. In some examples, a suitable acid may beconfigured to increase the solubility of a metallic material, such ascobalt, in the processing mixture, thereby facilitating leaching of themetallic material from superabrasive table 14 using the processingmixture. In additional examples, an acid may be configured to increasethe solubility of iron, tungsten, and/or nickel in the processingmixture.

Processing solution 72 may comprise a complexing agent dissolved in thesolvent. The complexing agent may comprise a compound suitable forforming metal complexes with various interstitial materials, including,for example, tungsten and/or tungsten carbide. The complexing agent mayform metal complexes with tungsten and/or tungsten carbide present in asuperabrasive material, thereby inhibiting or preventing the formationand/or build-up of tungsten oxides, such as WO₂, W₂O₅, and WO₃, in thesuperabrasive material. Metal complexes formed between the complexingagent and tungsten and/or tungsten carbide may be soluble in processingsolution 72, thereby enabling the metal complexes to be easily removedfrom superabrasive table 14. Accordingly, the complexing agent mayfacilitate the removal of tungsten and/or tungsten carbide from aleached portion of superabrasive table 14, thereby reducing the amountof residual tungsten, tungsten carbide, and/or tungsten oxide present ina leached region of superabrasive table 14. The complexing agent mayalso facilitate removal of additional metal compounds that may bepresent in superabrasive table 14. Examples of suitable compounds thatmay function as complexing agents include, without limitation,phosphoric acid, citric acid, tartaric acid, oxalic acid, ammoniumchloride, and/or any combination of the foregoing.

In various embodiments, processing solution 72 may optionally includeone or more of an electrolyte (e.g., acetic acid, ammonium chloride,arsenic acid, ascorbic acid, citric acid, formic acid, hydrobromic acid,hydrofluoric acid, hydroiodic acid, lactic acid, malic acid, nitricacid, oxalic acid, phosphoric acid, propionic acid, pyruvic acid,succinic acid, tartaric acid, carboxylic acid, etc.), an acid (e.g.,nitric acid, hydrochloric acid, phosphoric acid, sulfuric acid, boricacid, hydrofluoric acid, etc.), a metal salt (e.g., cobalt salts, ironsalts, etc.), a buffering agent (e.g., boric acid, an amine compoundsuch as ethylenediamine, triethanolamine, ethanolamine, etc.), a pHcontrol agent (e.g., sodium hydroxide, etc.), a conducting agent (e.g.,sodium sulfate, ammonium citrate, etc.), a complexing agent (e.g.,phosphoric acid, citric acid, tartaric acid, oxalic acid, ammoniumchloride, etc.), and/or combinations of the foregoing, withoutlimitation.

Electrode 40 may comprise any suitable size, shape, and/or geometry,without limitation. According to at least one embodiment, at least aportion of electrode 40 may be substantially disk shaped. For example,electrode 40 may comprise a disk shape having a circular or non-circularperiphery. Electrode 40 may comprise a suitable electrically conductivematerial, such as, for example, a metallic, semi-metallic, and/orgraphitic material. For example electrode 40 may include, withoutlimitation, copper, tungsten carbide, cobalt, zinc, iron, platinum,palladium, niobium, graphite, graphene, nichrome, gold, silver, alloysthereof, any suitable metallic material, and/or any other suitableelectrically conductive material, without limitation.

According to various embodiments, a charge may be applied tosuperabrasive element 10 and electrode 40 through electrical conductors44 and 42, respectively. For example, in order to apply a current toprocessing solution 72 for processing superabrasive element 10, at leasta portion of superabrasive element 10 may be positioned in processingsolution 72 and a charge may be applied to at least a portion ofsuperabrasive element 10 (e.g., rear surface 18 of substrate 12) throughelectrical conductor 44. For example, a positive charge may be appliedto substrate 12 such that at least a portion of superabrasive element 10acts as an anode. An opposite charge may be applied to electrode 40through electrical conductor 42. For example, a negative charge may beapplied to electrode 40 such that electrode 40 acts as a cathode. In atleast one embodiment, electrical conductor 44 may be electricallyconnected to substrate 12 by an electrode electrically connected to(e.g., positioned abutting) substrate 12. In some embodiments,electrical conductor 44 may be directly connected to superabrasive table14 by an electrode electrically connected to (e.g., positioned abuttingand/or disposed at least partially within) superabrasive table 14.

According to some embodiments, a voltage of less than approximately 10 Vmay be applied to processing solution 72 via electrode 40 andsuperabrasive element 10. In some embodiments, a voltage of betweenapproximately 0.01 V and approximately 5 V may be applied to processingsolution 72. In some embodiments, a voltage of between approximately 0.5V and approximately 3 V may be applied to processing solution 72. Insome embodiments, a voltage of between approximately 0.1 V andapproximately 3 V may be applied to processing solution 72. Inadditional embodiments, a voltage of between approximately 0.4 V andapproximately 2.4 V may be applied to processing solution 72. In someembodiments, a voltage of approximately 0.5 V, 0.6 V, 0.7 V, 0.8 V, 0.9V, or 1.0 V may be applied to processing solution 72.

In various embodiments, a voltage applied to processing solution 72 maybe changed one or more times while superabrasive element 10 is exposedto processing solution 72. For example, the electrical conductivity ofprocessing solution 72 may change during processing of superabrasiveelement 10 such that different voltages are required over time tomaintain a desired current flow between superabrasive element 10 andelectrode 40. In at least one embodiment, for example, materials removedfrom superabrasive element 10 and dissolved in processing solution 72during processing may cause processing solution 72 to decrease inelectrical conductivity and increase in electrical resistance. Thevoltage between superabrasive element 10 and electrode 40 may beincreased in conjunction with the decrease in electricalconductivity/increase in electrical resistance so as to maintain adesired current flow through superabrasive element 10 and/or processingsolution 72.

When superabrasive element 10 and electrode 40 are disposed in theprocessing solution 72 such that at least a portion of superabrasivetable 14 and electrode 40 are exposed to processing solution 72 and avoltage is applied to processing solution 72 via electrode 40 andsuperabrasive table 14, interstitial materials may be removed from atleast a portion of superabrasive table 14 and electrodeposited onto aportion of electrode 40 exposed to electroplating solution 72. Forexample, a metallic material, such as cobalt, present in at least aportion of superabrasive table 14 may be electrolytically oxidized inthe presence of a current flowing between superabrasive element 10 andelectrode 40. The oxidized metallic material may then be leached intoprocessing solution 72 as dissolved metal cations. Dissolved metalcations (e.g., cobalt cations) present in processing solution 72 maythen be reduced at electrode 40 to form a metal coating on a surfaceportion of electrode 40. Accordingly, a metallic material, such ascobalt, may be effectively transferred from at least a portion ofsuperabrasive table 14 of superabrasive element 10 to a surface portionof electrode 40 through electrodeposition of the metallic material ontothe surface portion of electrode 40.

In additional embodiments, a negative charge may be applied tosuperabrasive element 10 such that at least a portion of superabrasiveelement 10 acts as a cathode and a positive charge may be applied toelectrode 40 such that electrode 40 acts as an anode. A metallicmaterial present in superabrasive table 14 may be reduced to form metalanions that are dissolved in processing solution 72 and the dissolvedmetallic anions may then be electrodeposited through oxidation onto asurface portion of electrode 40.

According to various embodiments, superabrasive table 14 may be exposedto processing solution 72 at a desired temperature and/or pressure priorto and/or during leaching. Exposing superabrasive table 14 to a selectedtemperature and/or pressure during leaching may increase the depth towhich the superabrasive table 14 may be leached. Exposing superabrasivetable 14 to a selected temperature and/or pressure during leaching maydecrease an amount of time required to leach superabrasive table 14 to adesired degree.

In various examples, at least a portion of superabrasive element 10 andprocessing solution 72 may be heated to a temperature of betweenapproximately 15° C. and approximately 280° C. during leaching.According to additional embodiments, at least a portion of asuperabrasive element 10 and processing solution 72 may be heated to atemperature of between approximately 20° C. and approximately 95° C.during leaching. For example, at least a portion of a superabrasiveelement 10 and processing solution 72 may be heated to a temperature ofapproximately 25° C.

In various embodiments, at least a portion of superabrasive element 10and processing solution 72 may be exposed to a pressure of betweenapproximately 0 bar and approximately 100 bar during leaching. Inadditional embodiments, at least a portion of superabrasive element 10and processing solution 72 may be exposed to a pressure of betweenapproximately 20 bar and approximately 80 bar during leaching. In atleast one example, at least a portion of superabrasive element 10 andprocessing solution 72 may be exposed to a pressure of approximately 50bar during leaching.

According to additional embodiments, at least a portion of superabrasiveelement 10 and processing solution 72 may be exposed to at least one ofmicrowave radiation, and/or ultrasonic energy. By exposing at least aportion of superabrasive element 10 to microwave radiation, inductionheating, and/or ultrasonic energy as superabrasive element 10 is exposedto processing solution 72, the rate at which superabrasive table 14 isleached may be increased.

FIGS. 10A-10E show exemplary superabrasive elements 110 and assembliesfor leaching superabrasive elements 110. FIG. 10A is a cross-sectionalside view of an exemplary leaching assembly according to at least oneembodiment. As shown in FIG. 10A, superabrasive element 110 may bedisposed near an electrode 140. Superabrasive element 110 may comprise asuperabrasive table 114 that is not affixed to or formed upon asubstrate (see superabrasive element 110 illustrated in FIGS. 3 and 4).Superabrasive element 110 may comprise a rear surface 118, asuperabrasive face 120, and an element side surface 122. Superabrasiveelement 110 may also comprise a chamfer 124 formed by superabrasivetable 114. Chamfer 124 may comprise an angular and/or rounded edgeformed between superabrasive side surface 122 and superabrasive face120. Superabrasive element 110 may also comprise a rear chamfer 119formed by superabrasive table 114 at the intersection of element sidesurface 122 and rear surface 118.

In some embodiments, as illustrated in FIG. 10A, superabrasive element110 may not be surrounded by a protective covering, such as a leachingcup. Optionally, superabrasive element 110 may be at least partiallycovered by a protective layer, such as a leaching cup and/or a maskinglayer. Superabrasive element 110 and electrode 140 may be positionedwithin a processing vessel 170. Processing vessel 170 may have a rearwall 174 and a side wall 173 defining a cavity 176. Rear wall 174 andside wall 173 may have any suitable shape, without limitation.Processing vessel 170 may include an opening 178 opposite rear wall 174.Cavity 176 may contain a suitable processing solution 172 such that atleast a portion of superabrasive element 110 is exposed to processingsolution 172. Superabrasive element 110 may be positioned in cavity 176so that superabrasive element 110 is disposed near and/or electricallyconnected to (e.g., abutting) electrode 140.

Electrode 140 may comprise any suitable size, shape, and/or geometry,without limitation. According to at least one embodiment, at least aportion of electrode 140 may be substantially disk shaped. For example,electrode 140 may comprise a disk shape having a circular ornon-circular periphery. Electrode 140 may comprise a suitableelectrically conductive material, such as, for example, a metallic,semi-metallic, and/or graphitic material. For example electrode 140 mayinclude, without limitation, copper, tungsten carbide, cobalt, zinc,iron, platinum, palladium, niobium, graphite, graphene, nichrome, gold,silver, alloys thereof, any suitable metallic material, and/or any othersuitable electrically conductive material, without limitation.

According to various embodiments, a charge may be applied tosuperabrasive element 110 and electrode 140 through electricalconductors 144 and 142, respectively. For example, in order to apply acurrent to processing solution 172 for processing superabrasive element110, at least a portion of superabrasive element 110 may be positionedin processing solution 172 and a charge may be applied to at least aportion of superabrasive element 110 (e.g., rear surface 118 ofsubstrate 112) through electrical conductor 144 and an opposite chargemay be applied to electrode 140 through electrical conductor 142. Insome embodiments, as shown in FIG. 10A, superabrasive element 110 may bedisposed on an electrode 145, which electrically connects electricalconductor 144 to superabrasive element 110. Electrode 145 may separatesuperabrasive element 110 from processing vessel 170, therebyfacilitating contact between a greater surface area of superabrasiveelement 110 and processing solution 172. Additionally, electrode 145 mayfacilitate positioning of superabrasive element 110 near electrode 140.Optionally, superabrasive element 110 may be positioned near rear wall174 of processing vessel 170 and/or may be connected to electricalconductor 144 without electrode 145.

In some embodiments, superabrasive element 110 may be coupled toelectrode 145, or optionally, to electrical conductor 144, throughbrazing, welding, soldering, adhesive bonding, mechanical fastening,and/or any other suitable bonding technique. For example, superabrasiveelement 110 may be bonded to electrode 145 or electrical conductor 144by a braze joint (e.g., a carbide forming braze such as a titanium-basedbraze, etc.). In at least one embodiment, such a braze joint may becoated with a protective layer (e.g., paint layer, epoxy layer, etc.).

In at least one embodiment, a positive charge may be applied tosuperabrasive element 110, which acts as an anode, via electricalconductor 144 and electrode 145. An opposite charge may be applied toelectrode 140 through electrical conductor 142. For example, a negativecharge may be applied to electrode 140 such that electrode 140 acts as acathode. When superabrasive element 110 and electrode 140 are disposedin the processing solution 172 such that at least a portion ofsuperabrasive table 114 and electrode 140 are exposed to processingsolution 172 and a voltage is applied to processing solution 172 viaelectrode 140 and superabrasive table 114, interstitial materials may beremoved from at least a portion of superabrasive table 114 andelectrodeposited onto a portion of electrode 140 exposed toelectroplating solution 172. Superabrasive element 110 may be exposed toprocessing solution 172 and/or a charge may be applied to processingsolution 172 until a desired level of leaching is obtained.

FIGS. 10B and 10C illustrate superabrasive elements that have beenleached to different extents. FIG. 10B shows a superabrasive element 110that has been leached substantially throughout superabrasive table 114.Accordingly, superabrasive table 114 may have a leached volume 123 thatsubstantially occupies the entire volume of superabrasive table 114.According to various embodiments, at least some of interstitial regionsin leached volume 123 may be at least partially filled with interstitialmaterial that is not removed by leaching.

FIG. 10C shows a superabrasive element 110 that has been partiallyleached. Superabrasive table 114 may include a first volume 121comprising an interstitial material and a second volume 123 having alower concentration of the interstitial material than first volume 121.As shown in FIG. 10B, first volume 121 may be surrounded by secondvolume 123 such that substantially all surface portions (i.e.,superabrasive face 120, element side surface 122, chamfer 124, chamfer119) of superabrasive table 114 are defined by second volume 123, fromwhich the interstitial material has been substantially removed.

FIGS. 10D and 10E show cross-sectional side views of exemplary leachingassemblies according to various embodiments. As shown in FIGS. 10D and10E, superabrasive element 110 may be disposed near a plurality ofelectrodes, including at least electrodes 140A and 140B. Superabrasiveelement 110 may comprise a superabrasive table 114 that is not affixedto or formed upon a substrate (see superabrasive element 110 illustratedin FIGS. 3 and 4). Superabrasive element 110 may comprise a rear surface118, a superabrasive face 120, an element side surface 122, a chamfer124 between superabrasive side surface 122 and superabrasive face 120,and a rear chamfer 119 between element side surface 122 and rear surface118.

In some embodiments, as illustrated in FIGS. 10D and 10E, superabrasiveelement 110 may not be surrounded by a protective covering, such as aleaching cup. Optionally, superabrasive element 110 may be at leastpartially covered by a protective layer, such as a leaching cup and/or amasking layer. Superabrasive element 110 and electrodes 140A and 140Bmay be positioned within a processing vessel 170. Processing vessel 170may have a rear wall 174 and a side wall 173 defining a cavity 176. Rearwall 174 and side wall 173 may have any suitable shape, withoutlimitation. Processing vessel 170 may include an opening 178 oppositerear wall 174. Cavity 176 may contain a suitable processing solution 172such that at least a portion of superabrasive element 110 is exposed toprocessing solution 172. Superabrasive element 110 may be positioned incavity 176 so that superabrasive element 110 is disposed near and/orelectrically connected to (e.g., abutting) electrode 140.

Electrodes 140A and 140B may comprise any suitable size, shape, and/orgeometry, without limitation. According to at least one embodiment, atleast a portion of each of electrode 140A and/or electrode 140B may besubstantially disk shaped. For example, electrode 140A and/or electrode140B may comprise a disk shape having a circular or non-circularperiphery. In some embodiments, electrode 140A and/or electrode 140B mayhave a suitable concave and/or convex surface shape. Electrode 140 maycomprise a suitable electrically conductive material, such as, forexample, a metallic, semi-metallic, and/or graphitic material.

Electrodes 140A and 140B may be disposed at any suitable locations withrespect to superabrasive element 110 and each other. For example,electrode 140A and electrode 140B may be disposed on opposite sides ofsuperabrasive element 110. For example, as illustrated in FIG. 10D,electrode 140A may be positioned near superabrasive face 120 andelectrode 140B may be positioned near rear surface 118. As illustratedin FIG. 10E, electrode 140A may be positioned near a portion of elementside surface 122 and electrode 140B may be positioned near anotherportion element side surface 122. Optionally, electrodes 140A and 140Bmay be disposed near the same and/or adjacent sides of superabrasiveelement 110. In certain embodiments, electrode 140A and/or electrode140B may be electrically connected to (e.g., positioned abutting) atleast a portion of superabrasive element 110.

In some embodiments, electrodes 140A and 140B may represent portions ofan annular or ring-shaped electrode peripherally surroundingsuperabrasive element 110, and electrical conductor 142A and/orelectrical conductor 142B may be electrically connected to the annularor ring-shaped electrode at one or more locations. For example,electrodes 140A and 140B may comprise sections or portions of an annularor ring-shaped body, and electrical conductors 142A and 142B may beelectrically connected to each section.

According to various embodiments, a charge may be applied tosuperabrasive element 110 through one or more electrical connections.For example, a charge may be applied to superabrasive element 110through electrical conductor 144A and/or electrical conductor 144B. Acharge may be applied to electrode 140A and/or electrode 140B throughelectrical conductor 142A and/or electrical conductor 142B,respectively. In order to apply a current to processing solution 172 forprocessing superabrasive element 110, at least a portion ofsuperabrasive element 110 may be positioned in processing solution 172and a charge may be applied to at least a portion of superabrasiveelement 110 through electrical conductor 144A and/or electricalconductor 144B and an opposite charge may be applied to electrode 140Aand/or electrode 140B through electrical conductor 142A and/orelectrical conductor 142B.

In some embodiments, superabrasive element 110 may be coupled toelectrical conductor 144A and/or electrical conductor 144B at anysuitable location (e.g., element side surface 122 as shown in FIG. 10D,or superabrasive face 120 and/or rear surface 118 as shown in FIG. 10E)through brazing, welding, soldering, adhesive bonding, mechanicalfastening, and/or any other suitable bonding technique. For example,superabrasive element 110 may be bonded to electrode 145 or electricalconductor 144 by a braze joint (e.g., a carbide forming braze such as atitanium-based braze, etc.). In at least one embodiment, such a brazejoint may be coated with a protective layer (e.g., paint layer, epoxylayer, etc.).

As shown in FIGS. 10D and 10E, a positive charge may be applied tosuperabrasive element 110, which acts as an anode, via electricalconductor 144A and/or electrical conductor 144B. A negative charge maybe applied to electrode 140A and/or 140B through electrical conductor142A and/or electrical conductor 142B, respectively, such that electrode140A and/or 140B acts as a cathode. When superabrasive element 110 andelectrodes 140A and 140B are disposed in the processing solution 172such that at least a portion of superabrasive table 114 and electrodes140A and 140B are exposed to processing solution 172 and a voltage isapplied to processing solution 172 via superabrasive table 114 andelectrode 140A and/or electrode 140B, interstitial materials may beremoved from at least a portion of superabrasive table 114 andelectrodeposited onto at least a portion of electrode 140A and/orelectrode 140B exposed to electroplating solution 172. Superabrasiveelement 110 may be exposed to processing solution 172 and/or a chargemay be applied to processing solution 172 until a desired level ofleaching is obtained.

According to some embodiments, once interstitial materials have beenremoved from a substantial portion of superabrasive table or onceinterstitial materials have been removed from superabrasive element 110to a selected leach depth, a material coupling electrical conductor 144Aand/or electrical conductor 144B to superabrasive element 110 may be atleast partially degraded by processing solution 172. For example, abraze joint bonding electrical conductor 144A and/or electricalconductor 144B to superabrasive table 114 may have a more positivereduction potential than an interstitial material (e.g., cobalt) withinsuperabrasive table 114. Accordingly, the interstitial material may bepreferentially degraded by processing solution 172 prior to substantialdegradation of the braze joint. Once the interstitial material issubstantially removed from superabrasive table 114 during leaching,processing solution 172 may more aggressively degrade the braze jointsuch that electrical conductor 144A and/or electrical conductor 144B areelectrically and/or physically disconnected from superabrasive element110.

FIGS. 11 and 12 illustrate an exemplary superabrasive element 310positioned near an exemplary electrode 340 according to at least oneembodiment. Electrode 340 may comprise any suitable size, shape and/orgeometry, without limitation. As illustrated in FIGS. 11 and 12,superabrasive element 310 may comprise a superabrasive table 314 affixedto or formed upon a substrate 312. Superabrasive table 314 may beaffixed to substrate 312 at interface 326, which may be a planar ornon-planar interface. Superabrasive element 310 may comprise a rearsurface 318, a superabrasive face 320, and an element side surface 315.In some embodiments, element side surface 315 may include a substrateside surface 316 formed by substrate 312 and a superabrasive sidesurface 322 formed by superabrasive table 314. Rear surface 318 may beformed by substrate 312. Superabrasive element 310 may also comprise achamfer 324 formed by superabrasive table 314.

According to various embodiments, a charge may be applied tosuperabrasive element 310 and electrode 340 through electricalconductors (e.g., wires or any suitable electrical conductor) 344 and342, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 310, superabrasive element 310and electrical conductor 344 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate312 (e.g., rear surface 318) of superabrasive element 310 throughelectrical conductor 344 and an opposite charge may be applied toelectrode 340 through electrical conductor 342. In at least oneembodiment, electrical conductor 344 may be electrically connected tosubstrate 312 by an electrode electrically connected to (e.g.,positioned abutting) substrate 312. In some embodiments, electricalconductor 344 may be directly connected to superabrasive table 314 by anelectrode electrically connected to (e.g., positioned abutting)superabrasive table 314.

According to at least one embodiment, at least a portion of electrode340 may comprise a substantially annular or ring-shaped body. Forexample, electrode 340 may comprise a substantially annular ringsurrounding a central axis (e.g., central axis 29 shown in FIGS. 1-2),as illustrated in FIGS. 11 and 12. When superabrasive element 310 andelectrode 340 are disposed in a processing solution such that at least aportion of superabrasive table 314 and electrode 340 are exposed to theprocessing solution and a voltage is applied to the processing solutionvia electrode 340 and superabrasive table 314, interstitial materialsmay be removed from at least a portion of superabrasive table 314 ofsuperabrasive element 310 exposed to the processing solution. In someembodiments, interstitial materials may be removed to greater depthsfrom surface portions of superabrasive table 314 disposed in relativelycloser proximity to electrode 340 than other surface portions ofsuperabrasive table 314. Accordingly, a peripheral region ofsuperabrasive table 314 defining chamfer 324 may be leached to a greaterdepth than a central region of superabrasive table 314.

FIGS. 13 and 14 illustrate an exemplary superabrasive element 410positioned near an exemplary electrode 440 according to at least oneembodiment. As illustrated in FIGS. 13 and 14, superabrasive element 410may comprise a superabrasive table 414 affixed to or formed upon asubstrate 412. Superabrasive element 410 may comprise a rear surface418, a superabrasive face 420, and an element side surface 415. In someembodiments, element side surface 415 may include a substrate sidesurface 416 formed by substrate 412 and a superabrasive side surface 422formed by superabrasive table 414. Rear surface 418 may be formed bysubstrate 412. Superabrasive element 410 may also comprise a chamfer 424formed by superabrasive table 414.

According to various embodiments, a charge may be applied tosuperabrasive element 410 and electrode 440 through electricalconductors (e.g., wires or any suitable electrical conductor) 444 and442, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 410, superabrasive element 410and electrical conductor 444 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate412 (e.g., rear surface 418) of superabrasive element 410 throughelectrical conductor 444 and an opposite charge may be applied toelectrode 440 through electrical conductor 442. In at least oneembodiment, electrical conductor 444 may be electrically connected tosubstrate 412 by an electrode electrically connected to (e.g.,positioned abutting) substrate 412. In some embodiments, electricalconductor 444 may be directly connected to superabrasive table 414 by anelectrode electrically connected to (e.g., positioned abutting)superabrasive table 414.

According to at least one embodiment, at least a portion of electrode440 may comprise a disk shape. For example, electrode 440 may comprise adisk having a substantially circular outer periphery surface surroundinga central axis (e.g., central axis 29 shown in FIGS. 1-2), asillustrated in FIGS. 13 and 14. In some embodiments, electrode 440 mayhave an outer diameter that is smaller than the outer diameter ofelement side surface 415 of superabrasive element 410 and/or smallerthan an inner diameter of chamfer 424. When superabrasive element 410and electrode 440 are disposed in a processing solution such that atleast a portion of superabrasive table 414 and electrode 440 are exposedto the processing solution and a voltage is applied to the processingsolution via electrode 440 and superabrasive table 414, interstitialmaterials may be removed from at least a portion of superabrasive table414 of superabrasive element 410 exposed to the processing solution. Insome embodiments, interstitial materials may be removed to greaterdepths from surface portions of superabrasive table 414 disposed inrelatively closer proximity to electrode 440 than other surface portionsof superabrasive table 414. Accordingly, an axially central region ofsuperabrasive table 414 may be leached to a greater depth than an outerperipheral region.

FIGS. 15-21 illustrate superabrasive elements and electrodes incross-sectional views. The electrodes illustrated in these figures areintended to be disk-shaped and/or ring-shaped (see, e.g., electrodes 340and 440 respectively shown in FIGS. 11 and 13).

FIG. 15 shows a cross-sectional side view of an exemplary superabrasiveelement 510 and an exemplary electrode 540 according to at least oneembodiment. As illustrated in FIG. 15, superabrasive element 510 maycomprise a superabrasive table 514 affixed to or formed upon a substrate512. Superabrasive table 514 may be affixed to substrate 512 atinterface 526. Superabrasive element 510 may comprise a rear surface518, a superabrasive face 520, and an element side surface 515, whichmay include a substrate side surface 516 formed by substrate 512 and asuperabrasive side surface 522 formed by superabrasive table 514.Superabrasive element 510 may also comprise a chamfer 524 formed bysuperabrasive table 514.

According to various embodiments, a charge may be applied tosuperabrasive element 510 and electrode 540 through electricalconductors (e.g., wires or any suitable electrical conductor) 544 and542, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 510, superabrasive element 510and electrical conductor 544 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate512 (e.g., rear surface 518) of superabrasive element 510 throughelectrical conductor 544 and an opposite charge may be applied toelectrode 540 through electrical conductor 542.

According to at least one embodiment, at least a portion of electrode540 may comprise a substantially cylindrical shape defining a recess546. For example, electrode 540 may comprise a substantially cylindricalouter surface, as illustrated in FIG. 15. Recess 546 may be definedwithin electrode 540 and may have a diameter that is greater than theouter diameter of element side surface 515 of superabrasive element 510.Electrode 540 may be disposed such that at least a portion of recess 546surrounds at least a portion of superabrasive table 514 of superabrasiveelement 510, as shown in FIG. 15. When superabrasive element 510 andelectrode 540 are disposed in the processing solution such that at leasta portion of superabrasive table 514 and electrode 540 are exposed tothe processing solution and a voltage is applied to the processingsolution via electrode 540 and superabrasive table 514, interstitialmaterials may be removed from at least a portion of superabrasive table514 exposed to the processing solution.

FIG. 16 shows a cross-sectional side view of an exemplary superabrasiveelement 610 positioned near an exemplary electrode 640 according to atleast one embodiment. As illustrated in FIG. 16, superabrasive element610 may comprise a superabrasive table 614 affixed to or formed upon asubstrate 612. Superabrasive table 614 may be affixed to substrate 612at interface 626. Superabrasive element 610 may comprise a rear surface618, a superabrasive face 620, and an element side surface 615, whichmay include a substrate side surface 616 formed by substrate 612 and asuperabrasive side surface 622 formed by superabrasive table 614.Superabrasive element 610 may also comprise a chamfer 624 formed bysuperabrasive table 614.

According to various embodiments, a charge may be applied tosuperabrasive element 610 and electrode 640 through electricalconductors (e.g., wires or any suitable electrical conductor) 644 and642, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 610, superabrasive element 610and electrical conductor 644 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate612 (e.g., rear surface 618) of superabrasive element 610 throughelectrical conductor 644 and an opposite charge may be applied toelectrode 640 through electrical conductor 642.

According to at least one embodiment, at least a portion of electrode640 may comprise a substantially cylindrical shape defining a recess646. For example, electrode 640 may comprise a substantially cylindricalouter surface, as illustrated in FIG. 16. Recess 646 may be definedwithin electrode 640 and may have a diameter that is substantially thesame as or smaller than the outer diameter of element side surface 615of superabrasive element 610. When superabrasive element 610 andelectrode 640 are disposed in the processing solution such that at leasta portion of superabrasive table 614 and electrode 640 are exposed tothe processing solution and a voltage is applied to the processingsolution via electrode 640 and superabrasive table 614, interstitialmaterials may be removed from at least a portion of superabrasive table614 of superabrasive element 610 exposed to the processing solution.

FIG. 17 shows a cross-sectional side view of an exemplary superabrasiveelement 710 positioned near an exemplary electrode 740 according to atleast one embodiment. As illustrated in FIG. 17, superabrasive element710 may comprise a superabrasive table 714 affixed to or formed upon asubstrate 712. Superabrasive table 714 may be affixed to substrate 712at interface 726. Superabrasive element 710 may comprise a rear surface718, a superabrasive face 720, and an element side surface 715, whichmay include a substrate side surface 716 formed by substrate 712 and asuperabrasive side surface 722 formed by superabrasive table 714.Superabrasive element 710 may also comprise a chamfer 724 formed bysuperabrasive table 714.

According to various embodiments, a charge may be applied tosuperabrasive element 710 and electrode 740 through electricalconductors (e.g., wires or any suitable electrical conductor) 744 and742, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 710, superabrasive element 710and electrical conductor 744 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate712 (e.g., rear surface 718) of superabrasive element 710 throughelectrical conductor 744 and an opposite charge may be applied toelectrode 740 through electrical conductor 742.

According to at least one embodiment, at least a portion of electrode740 may comprise a substantially cylindrical shape with a peripheralrecess 748 defined therein and extending circumferentially around atleast a peripheral portion of electrode 740. For example, peripheralrecess 748 may be defined between a face of electrode 740 locatednearest superabrasive element 710 and an outer peripheral surface ofelectrode 740, as illustrated in FIG. 17. When superabrasive element 710and electrode 740 are disposed in a processing solution such that atleast a portion of superabrasive table 714 and electrode 740 are exposedto the processing solution and a voltage is applied to the processingsolution via electrode 740 and superabrasive table 714, interstitialmaterials may be removed from at least a portion of superabrasive table714 of superabrasive element 710 exposed to the processing solution.

FIG. 18 shows a cross-sectional side view of an exemplary superabrasiveelement 810 and an exemplary electrode 840 according to at least oneembodiment. As illustrated in FIG. 18, superabrasive element 810 maycomprise a superabrasive table 814 affixed to or formed upon a substrate812. Superabrasive table 814 may be affixed to substrate 812 atinterface 826. Superabrasive element 810 may comprise a rear surface818, a superabrasive face 820, and an element side surface 815, whichmay include a substrate side surface 816 formed by substrate 812 and asuperabrasive side surface 822 formed by superabrasive table 814.Superabrasive element 810 may also comprise a chamfer 824 formed bysuperabrasive table 814.

According to various embodiments, a charge may be applied tosuperabrasive element 810 and electrode 840 through electricalconductors (e.g., wires or any suitable electrical conductor) 844 and842, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 810, superabrasive element 810and electrical conductor 844 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate812 (e.g., rear surface 818) of superabrasive element 810 throughelectrical conductor 844 and an opposite charge may be applied toelectrode 840 through electrical conductor 842.

Electrode 840 may be annular or ring-shaped and electrical conductor 842may be electrically connected to electrode 840 at one or more locations.For example, electrode 840 may comprise sections or portions of anannular or ring-shaped body, and electrical conductor 842 may beelectrically connected to each section. In at least one embodiment,electrical conductor 844 may be electrically connected to substrate 812by an electrode electrically connected to (e.g., positioned abutting)substrate 812. In some embodiments, electrical conductor 844 may bedirectly connected to superabrasive table 814 by an electrodeelectrically connected to (e.g., positioned abutting) superabrasivetable 814.

According to at least one embodiment, at least a portion of electrode840 may comprise a substantially tilted annular or ring-shaped body. Forexample, electrode 840 may comprise an annular ring surrounding acentral axis (e.g., central axis 29 shown in FIGS. 1-2) and tilted at anangle, as illustrated in FIG. 18. Electrode 840 may be disposed in aposition such that at least a portion of electrode 840 surrounds atleast a portion of superabrasive table 814 of superabrasive element 810,such as chamfer 824, as shown in FIG. 18. In some embodiments, electrode840 may be tilted at substantially the same angle as chamfer 824. Whensuperabrasive element 810 and electrode 840 are disposed in theprocessing solution such that at least a portion of superabrasive table814 and electrode 840 are exposed to the processing solution and avoltage is applied to the processing solution via electrode 840 andsuperabrasive table 814, interstitial materials may be removed from atleast a portion of superabrasive table 814 of superabrasive element 810exposed to the processing solution. In some embodiments, interstitialmaterials may be removed to greater depths from surface portions ofsuperabrasive table 814 disposed in relatively closer proximity toelectrode 840 than other surface portions of superabrasive table 814.Accordingly, a peripheral region of superabrasive table 814 definingchamfer 824 may be leached to a greater depth than a central region ofsuperabrasive table 814.

FIG. 19 shows a cross-sectional side view of an exemplary superabrasiveelement 910 and an exemplary electrode 940 according to at least oneembodiment. As illustrated in FIG. 19, superabrasive element 910 maycomprise a superabrasive table 914 affixed to or formed upon a substrate912. Superabrasive table 914 may be affixed to substrate 912 atinterface 926. Superabrasive element 910 may comprise a rear surface918, a superabrasive face 920, and an element side surface 915, whichmay include a substrate side surface 916 formed by substrate 912 and asuperabrasive side surface 922 formed by superabrasive table 914.Superabrasive element 910 may also comprise a chamfer 924 formed bysuperabrasive table 914.

According to various embodiments, a charge may be applied tosuperabrasive element 910 and electrode 940 through electricalconductors (e.g., wires or any suitable electrical conductor) 944 and942, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 910, superabrasive element 910and electrical conductor 944 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate912 (e.g., rear surface 918) of superabrasive element 910 throughelectrical conductor 944 and an opposite charge may be applied toelectrode 940 through electrical conductor 942.

Electrode 940 may be annular or ring-shaped and electrical conductor 942may be electrically connected to electrode 940 at one or more locations.For example, electrode 940 may comprise sections or portions of anannular or ring-shaped body, and electrical conductor 942 may beelectrically connected to each section. In at least one embodiment,electrical conductor 944 may be electrically connected to substrate 912by an electrode electrically connected to (e.g., positioned abutting)substrate 912. In some embodiments, electrical conductor 944 may bedirectly connected to superabrasive table 914 by an electrodeelectrically connected to (e.g., positioned abutting) superabrasivetable 914.

According to at least one embodiment, at least a portion of electrode940 may comprise a substantially annular or ring-shaped body. Forexample, electrode 940 may comprise a substantially annular ringsurrounding a central axis (e.g., central axis 29 shown in FIGS. 1-2),as illustrated in FIG. 19. In at least one embodiment, electrode 940 mayhave an inner diameter that is greater than the outer diameter ofelement side surface 915 of superabrasive element 910. Electrode 940 maybe disposed in a position such that at least a portion of electrode 940surrounds at least a portion of superabrasive table 914 of superabrasiveelement 910, as shown in FIG. 19. When superabrasive element 910 andelectrode 940 are disposed in the processing solution such that at leasta portion of superabrasive table 914 and electrode 940 are exposed tothe processing solution and a voltage is applied to the processingsolution via electrode 940 and superabrasive table 914, interstitialmaterials may be removed from at least a portion of superabrasive table914 of superabrasive element 910 exposed to the processing solution. Insome embodiments, interstitial materials may be removed to greaterdepths from surface portions of superabrasive table 914 disposed inrelatively closer proximity to electrode 940 than other surface portionsof superabrasive table 914. Accordingly, a peripheral region ofsuperabrasive table 914 defining chamfer 924 and/or superabrasive sidesurface 922 may be leached to a greater depth than a central region ofsuperabrasive table 914.

FIG. 20 shows a cross-sectional side view of an exemplary superabrasiveelement 1010 and an exemplary electrode 1040 according to at least oneembodiment. As illustrated in FIG. 20, superabrasive element 1010 maycomprise a superabrasive table 1014 affixed to or formed upon asubstrate 1012. Superabrasive table 1014 may be affixed to substrate1012 at interface 1026. Superabrasive element 1010 may comprise a rearsurface 1018, a superabrasive face 1020, and an element side surface1015, which may include a substrate side surface 1016 formed bysubstrate 1012 and a superabrasive side surface 1022 formed bysuperabrasive table 1014. Superabrasive element 1010 may also comprise achamfer 1024 formed by superabrasive table 1014.

According to various embodiments, a charge may be applied tosuperabrasive element 1010 and electrode 1040 through electricalconductors (e.g., wires or any suitable electrical conductor) 1044 and1042, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 1010, superabrasive element1010 and electrical conductor 1044 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate1012 (e.g., rear surface 1018) of superabrasive element 1010 throughelectrical conductor 1044 and an opposite charge may be applied toelectrode 1040 through electrical conductor 1042.

Electrode 1040 may be annular or ring-shaped and electrical conductor1042 may be electrically connected to electrode 1040 at one or morelocations. For example, electrode 1040 may comprise sections or portionsof an annular or ring-shaped body, and electrical conductor 1042 may beelectrically connected to each section. In at least one embodiment,electrical conductor 1044 may be electrically connected to substrate1012 by an electrode electrically connected to (e.g., positionedabutting) substrate 1012. In some embodiments, electrical conductor 1044may be directly connected to superabrasive table 1014 by an electrodeelectrically connected to (e.g., positioned abutting) superabrasivetable 1014.

According to at least one embodiment, at least a portion of electrode1040 may comprise a substantially annular or ring-shaped body and maydefine a recess 1046, as illustrated in FIG. 20. In at least oneembodiment, a surface of electrode 1040 defining recess 1046 may have adiameter that is greater than the outer diameter of element side surface1015 of superabrasive element 1010. Electrode 1040 may be disposed in aposition such that at least a portion of recess 1046 surrounds at leasta portion of superabrasive table 1014 of superabrasive element 1010, asshown in FIG. 20. When superabrasive element 1010 and electrode 1040 aredisposed in the processing solution such that at least a portion ofsuperabrasive table 1014 and electrode 1040 are exposed to theprocessing solution and a voltage is applied to the processing solutionvia electrode 1040 and superabrasive table 1014, interstitial materialsmay be removed from at least a portion of superabrasive table 1014 ofsuperabrasive element 1010 exposed to the processing solution. In someembodiments, interstitial materials may be removed to greater depthsfrom surface portions of superabrasive table 1014 disposed in relativelycloser proximity to electrode 1040 than other surface portions ofsuperabrasive table 1014. Accordingly, a peripheral region ofsuperabrasive table 1014 defining chamfer 1024 and/or superabrasive sidesurface 1022 may be leached to a greater depth than a central region ofsuperabrasive table 1014.

FIG. 21 shows a cross-sectional side view of an exemplary superabrasiveelement 1110 and an exemplary electrode assembly 1140 comprising a firstelectrode 1141 and a second electrode 1143 according to at least oneembodiment. As illustrated in FIG. 21, superabrasive element 1110 maycomprise a superabrasive table 1114 affixed to or formed upon asubstrate 1112. Superabrasive table 1114 may be affixed to substrate1112 at interface 1126. Superabrasive element 1110 may comprise a rearsurface 1118, a superabrasive face 1120, and an element side surface1115, which may include a substrate side surface 1116 formed bysubstrate 1112 and a superabrasive side surface 1122 formed bysuperabrasive table 1114. Superabrasive element 1110 may also comprise achamfer 1124 formed by superabrasive table 1114.

According to various embodiments, a charge may be applied tosuperabrasive element 1110 and electrode assembly 1140 throughelectrical conductors (e.g., wires or any suitable electrical conductor)1144 and 1142, respectively. For example, in order to apply a current toa processing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 1110, superabrasive element1110 and electrical conductor 1144 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate1112 (e.g., rear surface 1118) of superabrasive element 1110 throughelectrical conductor 1144 and an opposite charge may be applied toelectrode assembly 1140 through electrical conductor 1142.

At least a portion of electrode assembly 1140 may be annular orring-shaped and electrical conductor 1142 may be electrically connectedto electrode assembly 1140 at one or more locations. For example, secondelectrode 1143 may comprise sections or portions of an annular orring-shaped body, and electrical conductor 1142 may be electricallyconnected to each section. In at least one embodiment, electricalconductor 1144 may be electrically connected to substrate 1112 by anelectrode electrically connected to (e.g., positioned abutting)substrate 1112. In some embodiments, electrical conductor 1144 may bedirectly connected to superabrasive table 1114 by an electrodeelectrically connected to (e.g., positioned abutting) superabrasivetable 1114.

According to at least one embodiment, first electrode 1141 may comprisea disk-shaped electrode positioned near superabrasive face 1120 ofsuperabrasive table 1114. Second electrode 1143 may comprise asubstantially annular or ring-shaped body with an inner diameter that isgreater than an outer diameter of element side surface 1115 ofsuperabrasive element 1110. Second electrode 1143 of electrode assembly1140 may be disposed in a position such that at least a portion ofsecond electrode 1143 surrounds at least a portion of superabrasivetable 1114 of superabrasive element 1110, as shown in FIG. 21. Whensuperabrasive element 1110 and electrode assembly 1140 are disposed inthe processing solution such that at least a portion of superabrasivetable 1114, first electrode 1141, and second electrode 1143 are exposedto the processing solution and a voltage is applied to the processingsolution via electrode assembly 1140 and superabrasive table 1114,interstitial materials may be removed from at least a portion ofsuperabrasive table 1114 of superabrasive element 1110 exposed to theprocessing solution. In some embodiments, interstitial materials may beremoved to greater depths from surface portions of superabrasive table1114 disposed in relatively closer proximity to first electrode 1141and/or second electrode 1143 of electrode assembly 1140 than othersurface portions of superabrasive table 1114.

FIG. 22 shows a cross-sectional side view of an exemplary superabrasiveelement 1210 and exemplary electrodes 1240 and 1249 according to atleast one embodiment. As illustrated in FIG. 22, superabrasive element1210 may comprise a superabrasive table 1214 affixed to or formed upon asubstrate 1212. Superabrasive table 1214 may be affixed to substrate1212 at interface 1226. Superabrasive element 1210 may comprise a rearsurface 1218, a superabrasive face 1220, and an element side surface1215, which may include a substrate side surface 1216 formed bysubstrate 1212 and a superabrasive side surface 1222 formed bysuperabrasive table 1214. Superabrasive element 1210 may also comprise achamfer 1224 formed by superabrasive table 1214.

As shown in FIG. 22, electrode 1249 may be disposed adjacent to at leastportion of superabrasive table 1214. For example, electrode 1249 may beelectrically connected to (e.g., positioned abutting) superabrasive face1220 and/or any other suitable surface of superabrasive table 1214.According to various embodiments, a charge may be applied to electrode1240 and electrode 1249, and likewise to superabrasive table 1214,through electrical conductors (e.g., wires or any suitable electricalconductor) 1242 and 1244, respectively. For example, in order to apply acurrent to a processing solution (e.g., processing solution 72illustrated in FIG. 9C) for processing superabrasive element 1210,superabrasive element 1210 and electrode 1249 may be positioned in theprocessing solution (e.g., optionally, with a leaching cup 30 or otherprotective covering) and a charge may be applied to at least a portionof superabrasive table 1214 through electrical conductor 1244 andelectrode 1249, and an opposite charge may be applied to electrode 1240through electrical conductor 1242.

According to at least one embodiment, electrode 1249 may comprise adisk-shaped electrode. In some embodiments, superabrasive table 1214 maybe coupled to electrode 1249 through brazing, welding, soldering,adhesive bonding, mechanical fastening, and/or any other suitablebonding technique. For example, superabrasive table 1214 may be bondedto electrode 1249 by a braze joint (e.g., a carbide forming braze suchas a titanium-based braze, etc.). In at least one embodiment, such abraze joint may be coated with a protective layer (e.g., paint layer,epoxy layer, etc.).

At least a portion of electrode 1240 may be annular or ring-shaped andelectrical conductor 1242 may be electrically connected to electrode1240 at one or more locations. For example, electrode 1240 may comprisesections or portions of an annular or ring-shaped body, and electricalconductor 1242 may be electrically connected to each section. Electrode1240 may be disposed in a position such that at least a portion ofelectrode 1240 surrounds at least a portion of superabrasive table 1214of superabrasive element 1210, as shown in FIG. 22. When superabrasiveelement 1210 and electrode 1240 are disposed in the processing solutionsuch that at least a portion of superabrasive table 1214 and electrode1240 are exposed to the processing solution and a voltage is applied tothe processing solution via electrode 1240, electrode 1249, and/orsuperabrasive table 1214, interstitial materials may be removed from atleast a portion of superabrasive table 1214 exposed to the processingsolution. In some embodiments, interstitial materials may be removed togreater depths from surface portions of superabrasive table 1214disposed in relatively closer proximity to electrode 1240 than othersurface portions of superabrasive table 1214.

FIGS. 23A and 23B show an exemplary superabrasive element 1310 coatedwith masking layers and disposed near an exemplary electrode 1340.According to various embodiments, portions of superabrasive element 1310may be coated or otherwise covered with one or more masking layers thatprevent and/or delay a leaching agent from contacting selected regionsof superabrasive element 1310 during leaching. For example, a firstmasking layer 1333 and a second masking layer 1335 may be formed on ordisposed abutting at least a portion of superabrasive element 1310.

As illustrated in FIGS. 23A and 23B, superabrasive element 1310 maycomprise a superabrasive table 1314 affixed to or formed upon asubstrate 1312. Superabrasive table 1314 may be affixed to substrate1312 at interface 1326. Superabrasive element 1310 may comprise a rearsurface 1318, a superabrasive face 1320, and an element side surface1315, which may include a substrate side surface 1316 formed bysubstrate 1312 and a superabrasive side surface 1322 formed bysuperabrasive table 1314. Superabrasive element 1310 may also comprise achamfer 1324 formed by superabrasive table 1314.

As shown in FIGS. 23A and 23B, first masking layer 1333 may be disposedon at least a portion of superabrasive face 1320, such as a centralportion of superabrasive face 1320 surrounding a central axis (e.g.,central axis 29 shown in FIGS. 1-2). Second masking layer 1335 may bedisposed on at least a portion of element side surface 1315 and rearsurface 1318 of superabrasive element 1310 so as to surround at least aportion of superabrasive table 1314 and/or substrate 1312. First maskinglayer 1333 and second masking layer 1335 may prevent damage to selectedportions of superabrasive element 1310 and may provide a desired leachprofile when superabrasive element 1310 is exposed to various leachingagents. For example, first masking layer 1333 and/or second maskinglayer 1335 may prevent or delay a leaching solution from contactingcertain portions of superabrasive element 1310, such as portions ofsubstrate 1312, portions of superabrasive table 1314, or both, duringleaching.

In various examples, first masking layer 1333 and/or second maskinglayer 1335 may comprise one or more materials that are substantiallyinert and/or otherwise resistant and/or impermeable to acids, bases,and/or other reactive compounds present in a leaching solution used toleach superabrasive element 1310. Optionally, first masking layer 1333and/or second masking layer 1335 may comprise a material that breaksdown or degrades in the presence of a leaching agent, such as a materialthat is at least partially degraded (e.g., at least partially dissolved)at a selected rate during exposure to the leaching agent.

In some embodiments, first masking layer 1333 and/or second maskinglayer 1335 may comprise one or more materials exhibiting significantstability during exposure to a leaching agent. According to variousembodiments, first masking layer 1333 and second masking layer 1335 maycomprise any suitable material, including metals, alloys, polymers,carbon allotropes, oxides, carbides, glass materials, ceramics,composites, membrane materials (e.g. permeable or semi-permeablematerials), and/or any combination of the foregoing, without limitation.First masking layer 1333 and second masking layer 1335 may be affixed tosuperabrasive element 1310 through any suitable mechanism, withoutlimitation, including, for example, direct bonding, bonding via anintermediate layer, such as an adhesive or braze joint, mechanicalattachment, such as mechanical fastening, frictional attachment, and/orinterference fitting. In some embodiments, first masking layer 1333and/or second masking layer 1335 may comprise a coating or layer ofmaterial that is formed on or otherwise adhered to at least a portion ofsuperabrasive element 1310. In additional embodiments, first maskinglayer 1333 and/or second masking layer 1335 may comprise a material thatis temporarily fixed to superabrasive element 1310. For example, firstmasking layer 1333 may comprise a polymer member (e.g., o-ring, gasket,disk) that is mechanically held in place (e.g., by clamping) duringexposure to a leaching agent.

First masking layer 1333 and second masking layer 1335 may be formedover any suitable portions superabrasive element 1310. For example, asillustrated in FIGS. 23A and 23B, first masking layer 1333 may be formedover a central portion of superabrasive face 1320 about a central axis(e.g., central axis 29 shown in FIGS. 1-2). First masking layer 1333 maybe separated from chamfer 1324. For example, first masking layer 1333may not be directly adjacent to and/or in contact with edge 1327 formedat the intersection of superabrasive face 1320 and chamfer 1324. Secondmasking layer 1333 may be formed over at least a portion of substrate1312 and superabrasive table 1314. For example, as shown in FIGS. 23Aand 23B, second masking layer 1335 may be formed over rear surface 1318and substrate side surface 1316 of substrate 1312 so as to substantiallysurround substrate 1312. Optionally, second masking layer 1335 may beformed over a portion of superabrasive side surface 1322. In someembodiments, second masking layer 1335 may also be separated fromchamfer 1324. For example, second masking layer 1335 may not be directlyadjacent to and/or in contact with edge 1328 formed at the intersectionof superabrasive side surface 1322 and chamfer 1324.

According to various embodiments, a charge may be applied tosuperabrasive element 1310 and electrode 1340 through electricalconductors (e.g., wires or any suitable electrical conductor) 1344 and1342, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 1310, superabrasive element1310 and electrical conductor 1344 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate1312 (e.g., rear surface 1318) of superabrasive element 1310 throughelectrical conductor 1344 and an opposite charge may be applied toelectrode 1340 through electrical conductor 1342. In at least oneembodiment, electrical conductor 1344 may be electrically connected tosubstrate 1312 by an electrode electrically connected to (e.g.,positioned abutting) substrate 1312. In some embodiments, electricalconductor 1344 may be directly connected to superabrasive table 1314 byan electrode electrically connected to (e.g., positioned abutting)superabrasive table 1314.

Electrode 1340 may comprise any suitable size, shape, and/or geometry,without limitation. In some embodiments, electrode 1340 may comprise acircular or non-circular disk shape. For example, electrode 1340 mayhave a substantially circular outer periphery surrounding a central axis(e.g., central axis 29 shown in FIGS. 1-2). Electrode 1340 may have anouter diameter that is larger than, the same as, or smaller than theouter diameter of element side surface 1315 of superabrasive element1310, as shown in FIGS. 23A and 23B. Electrodes and/or combinations ofelectrodes according to any of the configurations disclosed herein mayalso be utilized in addition to or in place of electrode 1340 forprocessing superabrasive element 1310. When superabrasive element 1310and electrode 1340 are disposed in the processing solution (e.g.,processing solution 72 as shown in FIG. 9C) such that at least a portionof superabrasive table 1314 and electrode 1340 are exposed to theprocessing solution and a voltage is applied to the processing solutionvia electrode 1340 and superabrasive table 1314, interstitial materialsmay be removed from at least a portion of superabrasive table 1314 ofsuperabrasive element 1310 exposed to the processing solution anddisposed near electrode 1340.

The configuration illustrated in FIGS. 23A and 23B may enable selectiveleaching of portions of superabrasive element 1310 to form a desiredleach profile within superabrasive table 1314. For example, a volume ofsuperabrasive table 1314 adjacent to an uncovered region between firstmasking layer 1333 and second masking layer 1335 may be leached to agreater depth than surrounding portions of superabrasive table 1314covered by first masking layer 1333 and second masking layer 1335. Theconfigurations illustrated in FIGS. 23A and 23B may result in theformation of leached volumes in portions of superabrasive table 1314located near chamfer 1324 during leaching. In some embodiments, theleached volumes may extend from chamfer 1324 to a region adjacent toand/or abutting interface 1326.

Following exposure to a leaching solution, first masking layer 1333and/or second masking layer 1335 may be substantially removed fromsuperabrasive table 1314 and/or substrate 1312 using any suitabletechnique, including, for example, lapping, grinding, and/or removalusing suitable chemical agents. According to certain embodiments, firstmasking layer 1333 and/or second masking layer 1335 may be peeled, cut,ground, lapped, and/or otherwise physically, thermally, or chemicallyremoved from superabrasive element 1310. In some embodiments, followingor during removal of first masking layer 1333 and/or second maskinglayer 1335, one or more surfaces of superabrasive table 1314 and/orsubstrate 1312 may be processed to form a desired surface texture and/orfinish using any suitable technique, including, for example, lapping,grinding, and/or otherwise physically and/or chemically treating the oneor more surfaces.

FIGS. 24 and 25 illustrate masking layers formed over portions of asuperabrasive element 1410 having an edge 1417 formed at theintersection of superabrasive face 1420 and superabrasive side surface1422. As illustrated, for example, in FIG. 24, first masking layer 1433may be formed over a central portion of superabrasive face 1420 about acentral axis (e.g., central axis 29 shown in FIGS. 1-2). First maskinglayer 1433 may not be directly adjacent to and/or in contact with edge1417. In additional embodiments, first masking layer 1433 may be formedadjacent to and/or in contact with edge 1417. Second masking layer 1435may be formed over at least a portion of substrate 1412 andsuperabrasive table 1414. For example, as shown in FIG. 24, secondmasking layer 1435 may be formed over rear surface 1418 and substrateside surface 1416 of substrate 1412 so as to substantially surroundsubstrate 1412. Optionally, second masking layer 1435 may be formed overa portion of superabrasive side surface 1422. In some embodiments,second masking layer 1435 may not be directly adjacent to and/or incontact with edge 1417, as shown in FIG. 24.

According to various embodiments, a charge may be applied tosuperabrasive element 1410 and electrode 1440 through electricalconductors (e.g., wires or any suitable electrical conductor) 1444 and1442, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 1410, superabrasive element1410 and electrical conductor 1444 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate1412 (e.g., rear surface 1418) of superabrasive element 1410 throughelectrical conductor 1444 and an opposite charge may be applied toelectrode 1440 through electrical conductor 1442. In at least oneembodiment, electrical conductor 1444 may be electrically connected tosubstrate 1412 by an electrode electrically connected to (e.g.,positioned abutting) substrate 1412. In some embodiments, electricalconductor 1444 may be directly connected to superabrasive table 1414 byan electrode electrically connected to (e.g., positioned abutting)superabrasive table 1414.

Electrode 1440 may comprise any suitable size, shape, and/or geometry,without limitation. In some embodiments, electrode 1440 may comprise acircular or non-circular disk shape. For example, electrode 1440 mayhave a substantially circular outer periphery surrounding a central axis(e.g., central axis 29 shown in FIGS. 1-2). Electrode 1440 may have anouter diameter that is larger than, the same as, or smaller than theouter diameter of element side surface 1415 of superabrasive element1410, as shown in FIG. 24. Electrodes according to any of theconfigurations disclosed herein may also be utilized in addition to orin place of electrode 1440 for processing superabrasive element 1410.When superabrasive element 1410 and electrode 1440 are disposed in theprocessing solution such that at least a portion of superabrasive table1414 and electrode 1440 are exposed to the processing solution and avoltage is applied to the processing solution via electrode 1440 andsuperabrasive table 1414, interstitial materials may be removed from atleast a portion of superabrasive table 1414 of superabrasive element1410 exposed to the processing solution and disposed near electrode1440.

FIG. 25 illustrates masking layers formed over portions of asuperabrasive element 1410 having an edge 1417 formed at theintersection of superabrasive face 1420 and superabrasive side surface1422. As illustrated, for example, in FIG. 25, first masking layer 1433may be formed over a central portion of superabrasive face 1420 about acentral axis (e.g., central axis 29 shown in FIGS. 1-2). First maskinglayer 1433 may not be directly adjacent to and/or in contact with edge1417. In additional embodiments, first masking layer 1433 may be formedadjacent to and/or in contact with edge 1417. Second masking layer 1435may be formed over at least a portion of substrate 1412 andsuperabrasive table 1414. For example, as shown in FIG. 25, secondmasking layer 1435 may be formed over rear surface 1418 and substrateside surface 1416 of substrate 1412 so as to substantially surroundsubstrate 1412. Optionally, second masking layer 1435 may be formed overa portion of superabrasive side surface 1422. In some embodiments,second masking layer 1435 may be disposed adjacent to and/or in contactwith edge 1417, as shown in FIG. 25.

According to various embodiments, a charge may be applied tosuperabrasive element 1410 and electrode 1440 through electricalconductors (e.g., wires or any suitable electrical conductor) 1444 and1442, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 1410, superabrasive element1410 and electrical conductor 1444 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate1412 (e.g., rear surface 1418) of superabrasive element 1410 throughelectrical conductor 1444 and an opposite charge may be applied toelectrode 1440 through electrical conductor 1442. In at least oneembodiment, electrical conductor 1444 may be electrically connected tosubstrate 1412 by an electrode electrically connected to (e.g.,positioned abutting) substrate 1412. In some embodiments, electricalconductor 1444 may be directly connected to superabrasive table 1414 byan electrode electrically connected to (e.g., positioned abutting)superabrasive table 1414.

Electrode 1440 may comprise any suitable size, shape, and/or geometry,without limitation. In some embodiments, electrode 1440 may comprise acircular or non-circular disk shape. For example, electrode 1440 mayhave a substantially circular outer periphery surrounding a central axis(e.g., central axis 29 shown in FIGS. 1-2). Electrode 1440 may have anouter diameter that is larger than, the same as, or smaller than theouter diameter of element side surface 1415 of superabrasive element1410, as shown in FIG. 25. When superabrasive element 1410 and electrode1440 are disposed in the processing solution such that at least aportion of superabrasive table 1414 and electrode 1440 are exposed tothe processing solution and a voltage is applied to the processingsolution via electrode 1440 and superabrasive table 1414, interstitialmaterials may be removed from at least a portion of superabrasive table1414 of superabrasive element 1410 exposed to the processing solutionand disposed near electrode 1440.

FIG. 26 shows an exemplary superabrasive element 1510 coated withmasking layers and disposed near an exemplary electrode 1540. Accordingto various embodiments, portions of superabrasive element 1510 may becoated or otherwise covered with one or more masking layers that preventand/or delay a leaching agent from contacting selected regions ofsuperabrasive element 1510 during leaching. For example, a first maskinglayer 1533 and, optionally, a second masking layer 1535 may be formed onor disposed abutting at least a portion of superabrasive element 1510.

Superabrasive element 1510 may comprise a superabrasive table 1514affixed to or formed upon a substrate 1512. Superabrasive table 1514 maybe affixed to substrate 1512 at interface 1526. Superabrasive element1510 may comprise a rear surface 1518, a superabrasive face 1520, and anelement side surface 1515, which may include a substrate side surface1516 formed by substrate 1512 and a superabrasive side surface 1522formed by superabrasive table 1514. Superabrasive element 1510 may alsocomprise a chamfer 1524 formed by superabrasive table 1514.

According to some embodiments, first masking layer 1533 and/or secondmasking layer 1535 may be disposed adjacent to and/or in contact with atleast a portion of chamfer 1524. For example, as illustrated in FIG. 26,first masking layer 1533 may substantially cover superabrasive face 1520such that first masking layer 1533 is formed adjacent to edge 1527 ofsuperabrasive table 1514. Optionally, second masking layer 1535 maysubstantially cover superabrasive side surface 1522 such that secondmasking layer 1535 is formed adjacent to edge 1528 of superabrasivetable 1514. In some embodiments, first masking layer 1533 and/or secondmasking layer 1535 may be formed over at least a portion chamfer 1524.

According to various embodiments, a charge may be applied tosuperabrasive element 1510 and electrode 1540 through electricalconductors (e.g., wires or any suitable electrical conductor) 1544 and1542, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 1510, superabrasive element1510 and electrical conductor 1544 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate1512 (e.g., rear surface 1518) of superabrasive element 1510 throughelectrical conductor 1544 and an opposite charge may be applied toelectrode 1540 through electrical conductor 1542. In at least oneembodiment, electrical conductor 1544 may be electrically connected tosubstrate 1512 by an electrode electrically connected to (e.g.,positioned abutting) substrate 1512. In some embodiments, electricalconductor 1544 may be directly connected to superabrasive table 1514 byan electrode electrically connected to (e.g., positioned abutting)superabrasive table 1514.

Electrode 1540 may comprise any suitable size, shape, and/or geometry,without limitation. In some embodiments, electrode 1540 may comprise acircular or non-circular disk shape. For example, electrode 1540 mayhave a substantially circular outer periphery surrounding a central axis(e.g., central axis 29 shown in FIGS. 1-2). Electrode 1540 may have anouter diameter that is larger than, the same as, or smaller than theouter diameter of element side surface 1515 of superabrasive element1510, as shown in FIG. 27. When superabrasive element 1510 and electrode1540 are disposed in the processing solution such that at least aportion of superabrasive table 1514 and electrode 1540 are exposed tothe processing solution and a voltage is applied to the processingsolution via electrode 1540 and superabrasive table 1514, interstitialmaterials may be removed from at least a portion of superabrasive table1514 of superabrasive element 1510 exposed to the processing solutionand disposed near electrode 1540. Accordingly, a peripheral region ofsuperabrasive table 1514 defining chamfer 1524 may be leached to agreater depth than a central region of superabrasive table 1514.

FIG. 27 is a cross-sectional side view of an exemplary superabrasiveelement 1610 coated with masking layers according to at least oneembodiment. As shown in FIG. 27, superabrasive element 1610 may becoated with various masking layers that prevent and/or delay a leachingagent from contacting selected regions of superabrasive element 1610during leaching. According to some embodiments, a first protectivemasking layer 1633 and a second protective masking layer 1635 may beformed on at least a portion of superabrasive element 1610. Optionally,a first at-least-partially-degrading masking layer 1637 and a secondat-least-partially-degrading masking layer 1647 may be formed on atleast a portion of superabrasive element 1610.

As illustrated in FIG. 27, superabrasive element 1610 may comprise asuperabrasive table 1614 affixed to or formed upon a substrate 1612.Superabrasive table 1614 may be affixed to substrate 1612 at interface1626. Superabrasive element 1610 may comprise a rear surface 1618, asuperabrasive face 1620, and an element side surface 1615, which mayinclude a substrate side surface 1616 formed by substrate 1612 and asuperabrasive side surface 1622 formed by superabrasive table 1614.Superabrasive element 1610 may also comprise a chamfer 1624 formed bysuperabrasive table 1614.

As shown in FIG. 27, first protective masking layer 1633 may be formedon at least a portion of superabrasive face 1620, such as a centralportion of superabrasive face 1620 surrounding a central axis (e.g.,central axis 29 shown in FIGS. 1-2). Second protective masking layer1635 may be formed on at least a portion of element side surface 1615and rear surface 1618 of superabrasive element 1610 so as to surround atleast a portion of superabrasive table 1614 and/or substrate 1612. Firstprotective masking layer 1633 and second protective masking layer 1635may prevent damage to selected portions of superabrasive element 10 andmay provide a desired leach profile when superabrasive element 1610 isexposed to various reactive agents. For example, first protectivemasking layer 1633 and/or second protective masking layer 1635 mayprevent or delay a leaching solution from contacting certain portions ofsuperabrasive element 1610, such as portions of substrate 1612, portionsof superabrasive table 1614, or both, during leaching. In variousexamples, first protective masking layer 1633 and/or second protectivemasking layer 1635 may comprise one or more materials that aresubstantially inert and/or otherwise resistant and/or impermeable toacids, bases, and/or other reactive compounds present in a leachingsolution used to leach superabrasive element 1610.

First at-least-partially-degrading masking layer 1637 may be formed onat least a portion of superabrasive element 1610 adjacent to firstprotective masking layer 1633. For example, firstat-least-partially-degrading masking layer 1637 may be formed onportions of superabrasive face 1620 and/or chamfer 1624. Secondat-least-partially-degrading masking layer 1647 may be formed on atleast a portion of superabrasive element 1610 adjacent to secondprotective masking layer 1635. For example, secondat-least-partially-degrading masking layer 1647 may be formed onportions of superabrasive side surface 1622 and/or chamfer 1624. Asshown in FIG. 27, first at-least-partially-degrading masking layer 1637may be separated from second at-least-partially-degrading masking layer1647. For example, a space between first at-least-partially-degradingmasking layer 1637 and second at-least-partially-degrading masking layer1647 may be formed over at least a portion of superabrasive table 1614,such as, for example, at least a portion of chamfer 1624. Optionally, aspace between first at-least-partially-degrading masking layer 1637 andsecond at-least-partially-degrading masking layer 1647 may also beformed over a portion of superabrasive face 1620 and/or superabrasiveside surface 1622.

According to at least one embodiment, first at-least-partially-degradingmasking layer 1637 and/or second at-least-partially-degrading maskinglayer 1647 may comprise a material that breaks down in the presence of aleaching agent. First at-least-partially-degrading masking layer 1637and/or second at-least-partially-degrading masking layer 1647 maycomprise, for example, a polymeric material that breaks down at adesired rate during exposure to the leaching agent. As firstat-least-partially-degrading masking layer 1637 and secondat-least-partially-degrading masking layer 1647 disintegrate duringleaching, portions of superabrasive element 1610 that were covered byfirst at-least-partially-degrading masking layer 1637 and secondat-least-partially-degrading masking layer 1647 may become exposed tothe leaching agent. According to additional embodiments, firstat-least-partially-degrading masking layer 1637 and/or secondat-least-partially-degrading masking layer 1647 may comprise a materialthat is more permeable to a leaching agent than first protective maskinglayer 1633 and/or second protective masking layer 1635. In at least oneembodiment, first at-least-partially-degrading masking layer 1637 and/orsecond at-least-partially-degrading masking layer 1647 may be notsubstantially degrade when exposed to a leaching agent but may besemi-permeable or permeable to the leaching agent.

First protective masking layer 1633, second protective masking layer1635, first at-least-partially-degrading masking layer 1637, and secondat-least-partially-degrading masking layer 1647 may each comprise anysuitable material, including metals, alloys, polymers, carbonallotropes, oxides, carbides, glass materials, ceramics, composites,membrane materials (e.g. permeable or semi-permeable materials), and/orany combination of the foregoing, without limitation. Further, firstprotective masking layer 1633, second protective masking layer 1635,first at-least-partially-degrading masking layer 1637, and secondat-least-partially-degrading masking layer 1647 may be affixed tosuperabrasive element 1610 through any suitable mechanism, withoutlimitation, including, for example, direct bonding, bonding via anintermediate layer, such as an adhesive or braze joint, mechanicalattachment, such as mechanical fastening, frictional attachment, and/orinterference fitting.

The configuration illustrated in FIG. 27 may enable selective leachingof portions of superabrasive element 1610 to form a desired leachprofile within superabrasive table 1614. For example, a volume ofsuperabrasive table 1614 adjacent to an uncovered region between firstat-least-partially-degrading masking layer 1637 and secondat-least-partially-degrading masking layer 1647 may be leached to agreater depth than surrounding portions of superabrasive table 1614. Asfirst at-least-partially-degrading masking layer 1637 and secondat-least-partially-degrading masking layer 1647 are degraded duringleaching, portions of superabrasive table 1614 that were covered byfirst at-least-partially-degrading masking layer 1637 and secondat-least-partially-degrading masking layer 1647 may subsequently beexposed to the leaching agent. Accordingly, volumes of superabrasivetable 1614 adjacent to the regions previously covered by firstat-least-partially-degrading masking layer 1637 and secondat-least-partially-degrading masking layer 1647 may be exposed to theleaching agent upon degradation of first at-least-partially-degradingmasking layer 1637 and second at-least-partially-degrading masking layer1647.

Accordingly, the regions of superabrasive table 1614 that wereoriginally adjacent to first at-least-partially-degrading masking layer1637 and second at-least-partially-degrading masking layer 1647 may havea shallower leach depth than regions of superabrasive table 1614 thatwere adjacent to the uncovered region between firstat-least-partially-degrading masking layer 1637 and secondat-least-partially-degrading masking layer 1647. For example, theconfiguration illustrated in FIG. 27 may result in a leach profilehaving a maximum leach depth in the volume of superabrasive table 1614adjacent to a central portion of chamfer 1624.

According to various embodiments, a charge may be applied tosuperabrasive element 1610 and electrode 1640 through electricalconductors (e.g., wires or any suitable electrical conductor) 1644 and1642, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 1610, superabrasive element1610 and electrical conductor 1644 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate1612 (e.g., rear surface 1618) of superabrasive element 1610 throughelectrical conductor 1644 and an opposite charge may be applied toelectrode 1640 through electrical conductor 1642. In at least oneembodiment, electrical conductor 1644 may be electrically connected tosubstrate 1612 by an electrode electrically connected to (e.g.,positioned abutting) substrate 1612. In some embodiments, electricalconductor 1644 may be directly connected to superabrasive table 1614 byan electrode electrically connected to (e.g., positioned abutting)superabrasive table 1614.

Electrode 1640 may comprise any suitable size, shape, and/or geometry,without limitation. In some embodiments, electrode 1640 may comprise acircular or non-circular disk shape. For example, electrode 1640 mayhave a substantially circular outer periphery surrounding a central axis(e.g., central axis 29 shown in FIGS. 1-2). Electrode 1640 may have anouter diameter that is larger than, the same as, or smaller than theouter diameter of element side surface 1615 of superabrasive element1610, as shown in FIG. 27. When superabrasive element 1610 and electrode1640 are disposed in the processing solution such that at least aportion of superabrasive table 1614 and electrode 1640 are exposed tothe processing solution and a voltage is applied to the processingsolution via electrode 1640 and superabrasive table 1614, interstitialmaterials may be removed from at least a portion of superabrasive table1614 of superabrasive element 1610 exposed to the processing solutionand disposed near electrode 1640. Accordingly, a peripheral region ofsuperabrasive table 1614 defining chamfer 1624 may be leached to agreater depth than a central region of superabrasive table 1614.

FIG. 28 is a cross-sectional side view of an exemplary superabrasiveelement 1710 coated with a masking layer and positioned within aleaching cup 1730 according to at least one embodiment. As illustratedin FIG. 28, a masking layer 1733 may be formed on or disposed adjacentto at least a portion of superabrasive face 1720, such as a centralportion of superabrasive face 1720 surrounding a central axis (e.g.,central axis 29 shown in FIGS. 1-2). According to at least oneembodiment, masking layer 1733 may comprise one or more materials thatare substantially inert and/or otherwise resistant and/or impermeable toacids, bases, and/or other reactive compounds present in a leachingsolution used to leach superabrasive element 1710.

As illustrated in FIG. 28, superabrasive element 1710 may comprise asuperabrasive table 1714 affixed to or formed upon a substrate 1712.Superabrasive table 1714 may be affixed to substrate 1712 at interface1726. Superabrasive element 1710 may comprise a rear surface 1718, asuperabrasive face 1720, and an element side surface 1715, which mayinclude a substrate side surface 1716 formed by substrate 1712 and asuperabrasive side surface 1722 formed by superabrasive table 1714.Superabrasive element 1710 may also comprise a chamfer 1724 formed bysuperabrasive table 1714.

As shown in FIG. 28, superabrasive element 1710 may be positioned withinprotective leaching cup 1730 such that protective leaching cup 1730surrounds at least a portion of superabrasive element 1710, includingsubstrate 1712. When superabrasive element 1710 is positioned withinprotective leaching cup 1730, at least a portion of superabrasiveelement 1710, such as superabrasive table 1714 and/or substrate 1712,may be positioned adjacent to and/or contacting a portion of protectiveleaching cup 1730. For example, protective leaching cup 1730 may beconfigured to contact at least a portion of element side surface 1715 ofsuperabrasive element 1710, forming a seal between protective leachingcup 1730 and superabrasive element 1710 that is partially or fullyimpermeable to various fluids, such as a leaching material (e.g., aleaching solution).

Protective leaching cup 1730 may be formed of any suitable material,without limitation. For example, protective leaching cup 1730 maycomprise a flexible, elastic, malleable, and/or otherwise deformablematerial configured to surround and/or contact at least a portion ofsuperabrasive element 1710. Protective leaching cup 1730 may preventdamage to superabrasive element 1710 when at least a portion ofsuperabrasive element 1710 is exposed to various leaching agents. Forexample, protective leaching cup 1730 may prevent a leaching solutionfrom chemically contacting and/or damaging certain portions ofsuperabrasive element 1710, such as portions of substrate 1712, portionsof superabrasive table 1714, or both, during leaching.

In various embodiments, protective leaching cup 1730 may comprise one ormore materials that are substantially inert and/or otherwise resistantto acids, bases, and/or other reactive components present in a leachingsolution used to leach superabrasive element 1710. In some embodiments,protective leaching cup 1730 may comprise one or more materialsexhibiting significant stability at various temperatures and/orpressures. In some embodiments, protective leaching cup 1730 may includeone or more polymeric materials, such as, for example, nylon,polytetrafluoroethylene (PTFE), polyethylene, polypropylene, rubber,silicone, and/or other polymers, and/or a combination of any of theforegoing, without limitation. For example, protective leaching cup 1730may comprise PTFE blended with one or more other polymeric materials.Protective leaching cup 1730 may be formed using any suitable technique.For example, protective leaching cup 1730 may comprise a polymericmaterial that is shaped through a molding process (e.g., injectionmolding, blow molding, compression molding, drawing, etc.) and/or amachining process (e.g., grinding, lapping, milling, boring, etc.).

In at least one embodiment, protective leaching cup 1730 may comprise amaterial that is configured to conform to an exterior portion ofsuperabrasive element 1710. For example, protective leaching cup 1730may include a malleable and/or elastically deformable material thatconforms to an exterior shape of a portion of superabrasive table 1714abutting protective leaching cup 1730, such as superabrasive sidesurface 1722. According to some embodiments, protective leaching cup1730 may comprise a material, such as a polymeric material (e.g.,elastomer, rubber, plastic, etc.), that conforms to surfaceimperfections of superabrasive side surface 1722 and/or substrate sidesurface 1716. Heat and/or pressure may be applied to protective leachingcup 1730 to cause a portion of protective leaching cup 1730 abuttingsuperabrasive side surface 1722 to more closely conform to superabrasiveside surface 1722. Accordingly, a seal between superabrasive sidesurface 1722 and a portion of protective leaching cup 1730 abuttingsuperabrasive side surface 1722 may be improved, thereby inhibitingpassage of a leaching agent between superabrasive element 1710 andprotective leaching cup 1730.

When superabrasive element 1710 is positioned within protective leachingcup 1730, at least a portion of superabrasive element 1710, such assuperabrasive table 1714 and/or substrate 1712, may be positionedadjacent to and/or contacting a portion of protective leaching cup 1730.For example, at least a portion of a seal region of protective leachingcup 1730 may be configured to contact at least a portion of element sidesurface 1715 of superabrasive element 1710, forming a seal betweenprotective leaching cup 1730 and superabrasive element 1710 that ispartially or fully impermeable to various fluids, such as a leachingagent. As shown in FIG. 28, superabrasive element 1710 may be positionedwithin protective leaching cup 1730 so that at least a portion of theseal region of protective leaching cup 1730 contacts and forms a sealwith at least a portion of element side surface 1715, such as at least aportion of superabrasive side surface 1722 and/or at least a portion ofsubstrate side surface 1716.

According to various embodiments, a charge may be applied tosuperabrasive element 1710 and electrode 1740 through electricalconductors (e.g., wires or any suitable electrical conductor) 1744 and1742, respectively. For example, in order to apply a current to aprocessing solution (e.g., processing solution 72 illustrated in FIG.9C) for processing superabrasive element 1710, superabrasive element1710 and electrical conductor 1744 may be positioned in the processingsolution (e.g., optionally, with a leaching cup 30 or other protectivecovering) and a charge may be applied to at least a portion of substrate1712 (e.g., rear surface 1718) of superabrasive element 1710 throughelectrical conductor 1744 and an opposite charge may be applied toelectrode 1740 through electrical conductor 1742. In at least oneembodiment, electrical conductor 1744 may be electrically connected tosubstrate 1712 by an electrode electrically connected to (e.g.,positioned abutting) substrate 1712. In some embodiments, electricalconductor 1744 may be directly connected to superabrasive table 1714 byan electrode electrically connected to (e.g., positioned abutting)superabrasive table 1714.

Electrode 1740 may comprise any suitable size, shape, and/or geometry,without limitation. In some embodiments, electrode 1740 may comprise acircular or non-circular disk shape. For example, electrode 1740 mayhave a substantially circular outer periphery surrounding a central axis(e.g., central axis 29 shown in FIGS. 1-2). Superabrasive element 1710may comprise any suitable size, shape, and/or geometry, withoutlimitation. For example, superabrasive element 1710 may comprise asubstantially cylindrical or non-cylindrical outer surface surrounding acentral axis (e.g., central axis 29 shown in FIGS. 1-2) of superabrasiveelement 1710. Electrode 1740 may have an outer diameter that is largerthan, the same as, or smaller than the outer diameter of element sidesurface 1715 of superabrasive element 1710, as shown in FIG. 28. Whensuperabrasive element 1710 and electrode 1740 are disposed in theprocessing solution such that at least a portion of superabrasive table1714 and electrode 1740 are exposed to the processing solution and avoltage is applied to the processing solution via electrode 1740 andsuperabrasive table 1714, interstitial materials may be removed from atleast a portion of superabrasive table 1714 of superabrasive element1710 exposed to the processing solution and disposed near electrode1740.

The configuration illustrated in FIG. 28 may enable selective leachingof portions of superabrasive element 1710 to form a desired leachprofile within superabrasive table 1714. For example, a volume ofsuperabrasive table 1714 adjacent to an uncovered region between maskinglayer 1733 and the seal region of protective leaching cup 1730 may beleached to a greater depth than surrounding portions of superabrasivetable 1714 covered by masking layer 1733 or the seal region. Leachingsuch a configuration may result in the formation of leached volumes inportions of superabrasive table 1714 located near chamfer 1724 duringleaching.

FIG. 29 is a perspective view of an exemplary leaching assembly 61according to at least one embodiment. As illustrated in FIG. 29,leaching assembly 61 may comprise a lower tray 60 and an upper tray 62.Lower tray 60 and upper tray 62 may comprise any suitable shape, suchas, for example, substantially disk-shaped bodies. According to variousembodiments, lower tray 60 and upper tray 62 may be connected by acylindrical shaft 68 supporting lower tray 60 and upper tray 62. Atleast one of lower tray 60 and upper tray 62 may be movable along shaft68 such that lower tray 60 and upper tray 62 may be supported adjacentto or separated from each other as desired.

A plurality of holes 64 (not all labeled) may be defined in lower tray60. In some embodiments, a plurality of holes 66 (not all labeled) mayalso be defined in upper tray 62. Holes 64 may each be configured tohold a superabrasive element 10. Holes 64 may be configured such thatsuperabrasive elements 10 are recessed in holes 64. Holes 64 may extendpartially or fully through lower tray 60. Holes 64 may extend throughlower tray 60 such that electrical conductors 44 (not all labeled) maybe electrically connected to superabrasive elements 10. Holes 66 definedin upper tray 62 may each be configured to hold an electrode 40 and/orelectrical conductor connected to electrode 40. In some embodiments,holes 66 may be configured such that each electrode 40 (not all labeled)is disposed near, but not contacting, a respective superabrasive element10 when lower tray 60 and upper tray 62 are positioned adjacent to eachother. Holes 66 may be configured such that at least a portion of eachelectrode 40 protrudes from upper tray 62 toward lower tray 60. Holes 66may extend through upper tray 62 such that electrical conductors 42 (notall labeled) may be electrically connected to electrodes 40.

According to at least one embodiment, leaching assembly 61 may beconfigured such that a volume of a processing solution 72 (e.g.,processing solution 72 illustrated in 10) is disposed in each of holes64. For example, processing solution 72 may be disposed in each hole 64such that processing solution 72 contacts and/or surrounds at least aportion of each superabrasive element 10. Accordingly, at least aportion of each superabrasive element 10, such as at least a portion ofsuperabrasive table 14, may be exposed to processing solution 72.Alternatively, lower tray 60 may be at least partially submersed in aprocessing solution and upper tray 62 may be at least partiallysubmersed in the processing solution.

Upper tray 62 containing electrodes 40 disposed in and/or protrudingfrom holes 66 may be positioned adjacent to lower tray 60 containingsuperabrasive elements 10 and processing solution 72 in holes 64. Uppertray 62 and lower tray 60 may be positioned such that at least a portionof each electrode 40 is disposed in holes 64 in contact with processingsolution 72. According to various embodiments, at least a portion oflower tray 60 and upper tray 62 may be sealed together so as to preventprocessing solution 72 from leaking from leaching assembly 61 duringprocessing.

According to various embodiments, a charge may be applied tosuperabrasive element 10 and electrode 40 through electrical conductors44 and 42, respectively. For example, in order to apply a current toprocessing solution 72 for processing superabrasive elements 10, acharge may be applied to at least a portion of each superabrasiveelement 10 through electrical conductors 44 and an opposite charge maybe applied to each electrode 40 through electrical conductors 42.

FIGS. 30-41B show superabrasive elements having exemplary leach profilesthat may be obtained by exemplary leach apparatuses disclosed herein.

FIG. 30 shows a cross-sectional side view of an exemplary superabrasiveelement 1810 according to at least one embodiment. As illustrated inFIG. 30, superabrasive element 1810 may comprise a superabrasive table1814 affixed to or formed upon a substrate 1812. Superabrasive table1814 may be affixed to substrate 1812 at interface 1826. Superabrasiveelement 1810 may comprise a rear surface 1818, a superabrasive face1820, and an element side surface 1815, which may include a substrateside surface 1816 formed by substrate 1812 and a superabrasive sidesurface 1822 formed by superabrasive table 1814. Superabrasive element1810 may also comprise a chamfer 1824 formed by superabrasive table1814.

As illustrated in FIG. 30, superabrasive table 1814 may include a firstvolume 1821 comprising an interstitial material and a second volume 1823having a lower concentration of the interstitial material than firstvolume 1821. Portions of superabrasive table 1814, such as second volume1823 may be leached or otherwise processed to remove interstitialmaterials, such as a metal-solvent catalyst, from the interstitialregions. Second volume 1823 may be created during leaching ofsuperabrasive table 1812 according to any suitable leaching technique.For example, second volume 1823 may be selectively leached by disposingportions of superabrasive table 1814 of superabrasive element 1810 nearan electrode during an electrochemical leaching process (e.g.,electrochemical leaching referenced in FIG. 9C). In some embodiments,superabrasive element 1810 may first be leached, after which portions ofsuperabrasive element 1810 may be removed to modify the shape of firstvolume 1821 and/or second volume 1823 according to one or more methodsdiscussed herein.

A transition region 1825 may extend between first volume 1821 and secondvolume 1823. Transition region 1825 may include amounts of metal-solventcatalyst varying between an amount of metal-solvent catalyst in firstvolume 1821 and an amount of metal-solvent catalyst in second volume1823. As illustrated in FIG. 30, first volume 1821 may be locatedadjacent to a central portion of superabrasive face 1820. For example,first volume 1821 may be disposed about central axis 1829. First volume1821 may extend between interface 1826 and superabrasive face 1820 withfirst volume 1821 forming at least a portion of superabrasive face 1820such that the central portion of superabrasive face 1820 located aboutcentral axis 1829 is defined by first volume 1821, as shown in FIG. 30.In some embodiments, first volume 1821 and superabrasive face 1820 maybe separated by a thin layer of leached polycrystalline diamond materiallocated adjacent to a central region of superabrasive face 1820.

Second volume 1823 may be formed around at least a portion of firstvolume 1821. For example, second volume 1823 may comprise an annularvolume surrounding at least a portion of first volume 1821 such that anouter portion of superabrasive face 1820 relative to central axis 1829is defined by second volume 1823. As shown in FIG. 30, second volume1823 may be located adjacent to superabrasive face 1820 and/or chamfer1824 so as to at least partially surround a portion of first volume 1821that is also adjacent to superabrasive face 1820. Second volume 1823 maybe located adjacent to element side surface 1815. Second volume 1823 maybe separated from interface 1826 between substrate 1812 andsuperabrasive table 1814 so as to prevent corrosion of substrate 1812 bya leaching solution used to form second volume 1823.

First volume 1821, second volume 1823, and transition region 1825 may beformed to any suitable size and/or shape within superabrasive table1814, without limitation. For example, transition region 1825 may extendalong a generally straight, angular, curved, and/or variable (e.g.,zigzag, undulating) profile between first volume 1821 and second volume1823. In various embodiments, transition region 1825 may comprise arelatively narrow region between first volume 1821 and second volume1823, while transition region 1825 may optionally comprise a relativelywider region between first volume 1821 and second volume 1823.

As shown in FIG. 30, second volume 1823 may have a depth 1836 fromsuperabrasive face 1820 in a direction substantially perpendicular tosuperabrasive face 1820. Second volume 1823 may comprise a generallyannular-shaped volume defined between a first diameter 1857 and a seconddiameter 1858 surrounding central axis 1829. The portion of first volume1821 surrounded by second volume 1823 may be generally defined by firstdiameter 1857. Second diameter 1858 may represent a diameter of elementside surface 1815. Edge 1827 formed at the intersection of chamfer 1824and superabrasive face 1820 may be located at a third diameter 1859relative to central axis 1829.

Second volume 1823 may be leached to any suitable depth fromsuperabrasive face 1820, chamfer 1824, and/or superabrasive side surface1822, without limitation. According to some embodiments, second volume1823 may have a leach depth greater than or equal to approximately 200μm as measured in a substantially perpendicular direction from at leastone of superabrasive face 1820, chamfer 1824, and/or superabrasive sidesurface 1822. In various embodiments, second volume 1823 may have aleach depth between approximately 200 μm and approximately 1200 μm(e.g., approximately 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950μm, 1000 μm, 1050 μm, 1100 μm, 1150 μm, or 1200 μm) as measured in asubstantially perpendicular direction from at least one of superabrasiveface 1820, chamfer 1824, and/or superabrasive side surface 1822.According to at least one embodiment, a depth of second volume 1823 asmeasured from a center portion of chamfer 1824 may be betweenapproximately 200 μm and 700 μm.

Superabrasive elements 1810 having superabrasive table 1814 comprisingfirst volume 1821 and second volume 1823 may exhibit properties ofincreased thermal stability, fatigue resistance, strength, and/or wearresistance. Such properties may be enhanced by the shape, size, and/orlocations of first volume 1821, second volume 1823, and/or transitionregion 1825 of superabrasive table 1814. Accordingly, the superabrasiveelement configuration illustrated in FIG. 30, as well as otherconfigurations illustrated and described herein, may provide significantresistance to undesired spalling, cracking, and/or thermal damage ofsuperabrasive portions, such as superabrasive table 1814, of thesuperabrasive elements during drilling.

FIG. 31 shows a cross-sectional side view of an exemplary superabrasiveelement 1910 according to at least one embodiment. As illustrated inFIG. 31, superabrasive element 1910 may comprise a superabrasive table1914 affixed to or formed upon a substrate 1912. Superabrasive table1914 may be affixed to substrate 1912 at interface 1926. Superabrasiveelement 1910 may comprise a rear surface 1918, a superabrasive face1920, and an element side surface 1915, which may include a substrateside surface 1916 formed by substrate 1912 and a superabrasive sidesurface 1922 formed by superabrasive table 1914. Superabrasive element1910 may also comprise a chamfer 1924 formed by superabrasive table1914.

Superabrasive element 1910 may include a first volume 1921 comprising aninterstitial material and a second volume 1923 having a lowerconcentration of the interstitial material than first volume 1921.Portions of superabrasive table 1914, such as second volume 1923, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 1925 may extend between first volume 1921 and second volume 1923so as to border at least a portion of first volume 1921 and secondvolume 1923. Transition region 1925 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 1921 and an amount of the interstitial materialin second volume 1923. In other embodiments, the boundary may be welldefined (i.e., transition region 1925 may be thin compared to a depth ofsecond volume 1923).

Transition region 1925 located between first volume 1921 and secondvolume 1923 may extend along any suitable profile within superabrasivetable 1914. For example, as illustrated in FIG. 31, sloped boundaryportion 1955 of transition region 1925 may extend between chamfer 1924and central boundary portion 1954 along any suitable profile, including,for example, a generally straight, angular, curved, and/or variable(e.g., zigzag, undulating) profile. According to at least oneembodiment, superabrasive element 1910 may be processed such thattransition region 1925 intersects chamfer 1924 and/or a surface regionadjacent to chamfer 1924 (e.g., superabrasive side surface 1922).Accordingly, as shown in FIG. 31, second volume 1923 may be locateddirectly adjacent to a central portion of superabrasive face 1920. Forexample, second volume 1923 may be disposed about central axis 1929. Aportion of first volume 1921, such as a portion adjacent to chamfer1924, may peripherally surround at least a portion of second volume1923.

FIG. 32 shows a cross-sectional side view of an exemplary superabrasiveelement 2010 according to at least one embodiment. As illustrated inFIG. 32, superabrasive element 2010 may comprise a superabrasive table2014 affixed to or formed upon a substrate 2012. Superabrasive table2014 may be affixed to substrate 2012 at interface 2026. Superabrasiveelement 2010 may comprise a rear surface 2018, a superabrasive face2020, and an element side surface 2015, which may include a substrateside surface 2016 formed by substrate 2012 and a superabrasive sidesurface 2022 formed by superabrasive table 2014. Superabrasive element2010 may also comprise a chamfer 2024 formed by superabrasive table2014.

Superabrasive element 2010 may include a first volume 2021 comprising aninterstitial material and a second volume 2023 having a lowerconcentration of the interstitial material than first volume 2021.Portions of superabrasive table 2014, such as second volume 2023, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 2025 may extend between first volume 2021 and second volume 2023so as to border at least a portion of first volume 2021 and secondvolume 2023. Transition region 2025 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 2021 and an amount of the interstitial materialin second volume 2023. In other embodiments, the boundary may be welldefined (i.e., transition region 2025 may be thin compared to a depth ofsecond volume 2023).

In some embodiments, as illustrated in FIG. 32, sloped boundary portion2055 of transition region 2025 may extend between superabrasive sidesurface 2022 and central boundary portion 2054 along any suitableprofile, including, for example, a generally straight, angular, curved,and/or variable (e.g., zigzag, undulating) profile. According to atleast one embodiment, superabrasive element 2010 may be processed suchthat transition region 2025 intersects superabrasive side surface 2022below chamfer 2024.

FIGS. 33-41B show cross-sectional views of superabrasive elementscomprising superabrasive tables having exemplary leach profiles that maybe obtained by exemplary leach apparatuses disclosed herein. Whilesuperabrasive elements illustrated in FIGS. 33-41B shown assuperabrasive tables without a substrate, the leach profiles illustratedin these figures may also apply to superabrasive elements (e.g.,superabrasive element 10 shown in FIGS. 1-2) comprising a superabrasiveelement bonded to a substrate. According to some embodiments, thesuperabrasive elements illustrated in FIGS. 33-41B may be formed byleaching a superabrasive element comprising a substrate and asuperabrasive table according to any of the techniques described hereinand subsequently separating (e.g., by lapping, grinding, wire EDM, etc.)the superabrasive table from the substrate. Alternatively, asuperabrasive element may be formed with a substrate, the substrate maybe removed, and then the superabrasive table may be leached.

FIG. 33 shows an exemplary superabrasive element 2110 comprising asuperabrasive table 2114 having a rear surface 2118, a superabrasiveface 2120, and an element side surface 2115. Superabrasive element 2110may comprise an edge 2117 (i.e., sloped or angled) and/or any othersuitable surface shape at the intersection of element side surface 2115and superabrasive face 2120, including, without limitation, an arcuatesurface (e.g., a radius, an ovoid shape, or any other rounded shape), asharp edge, multiple chamfers/radii, a honed edge, and/or combinationsof the foregoing. Element side surface 2115 of superabrasive element2110 may radially surround a central axis 2129 of superabrasive element2110.

Superabrasive element 2110 may include a first volume 2121 comprising aninterstitial material and a second volume 2123 having a lowerconcentration of the interstitial material than first volume 2121.Portions of superabrasive table 2114, such as second volume 2123, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 2125 may extend between first volume 2121 and second volume 2123so as to border at least a portion of first volume 2121 and secondvolume 2123. Transition region 2125 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 2121 and an amount of the interstitial materialin second volume 2123. In other embodiments, the boundary may be welldefined (i.e., transition region 2125 may be thin compared to a depth ofsecond volume 2123).

As shown in FIG. 33, first volume 2121 may extend between rear surface2118 and transition region 2125. Second volume 2123 may be formedadjacent to a substantial portion of superabrasive face 2120. Transitionregion 2125 bordering second volume 2123 may extend in a directiongenerally parallel to superabrasive face 2120. Optionally, a portion ofsecond volume 2123 may extend along at least a portion of element sidesurface 2115 so as to radially surround at least a portion of firstvolume 2121. A portion of transition region 2125 may extend in adirection generally parallel to element side surface 2115. According tosome embodiments, transition region 2125 may have a substantiallyconsistent thickness along element side surface 2115 and/or alongsuperabrasive face 2120.

FIG. 34 shows an exemplary superabrasive element 2210 comprising asuperabrasive table 2214 having a rear surface 2218, a superabrasiveface 2220, and an element side surface 2215. Superabrasive table 2214may also form a chamfer 2224 and one or more cutting edges, such as edge2227 and edge 2228, adjacent to chamfer 2224. Element side surface 2215of superabrasive element 2210 may radially surround a central axis 2229of superabrasive element 2210.

Superabrasive element 2210 may include a first volume 2221 comprising aninterstitial material and a second volume 2223 having a lowerconcentration of the interstitial material than first volume 2221.Portions of superabrasive table 2214, such as second volume 2223, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 2225 may extend between first volume 2221 and second volume 2223so as to border at least a portion of first volume 2221 and secondvolume 2223. Transition region 2225 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 2221 and an amount of the interstitial materialin second volume 2223. In other embodiments, the boundary may be welldefined (i.e., transition region 2225 may be thin compared to a depth ofsecond volume 2223).

As shown in FIG. 34, second volume 2223 may be formed adjacent tochamfer 2224 and superabrasive face 2220, and transition region 2225 mayextend from superabrasive face 2220 to edge 2228 formed at theintersection of chamfer 2224 and element side surface 2215, with aportion of transition region 2225 extending generally parallel tochamfer 2224.

FIG. 35 shows an exemplary superabrasive element 2310 comprising asuperabrasive table 2314 having a rear surface 2318, a superabrasiveface 2320, and an element side surface 2315. Superabrasive table 2314may also form a chamfer 2324 and one or more cutting edges, such as edge2327 and edge 2328, adjacent to chamfer 2324. Element side surface 2315of superabrasive element 2310 may radially surround a central axis 2329of superabrasive element 2310.

Superabrasive element 2310 may include a first volume 2321 comprising aninterstitial material and a second volume 2323 having a lowerconcentration of the interstitial material than first volume 2321.Portions of superabrasive table 2314, such as second volume 2323, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 2325 may extend between first volume 2321 and second volume 2323so as to border at least a portion of first volume 2321 and secondvolume 2323. Transition region 2325 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 2321 and an amount of the interstitial materialin second volume 2323. In other embodiments, the boundary may be welldefined (i.e., transition region 2325 may be thin compared to a depth ofsecond volume 2323).

As shown in FIG. 35, second volume 2323 may be formed adjacent tochamfer 2324, superabrasive face 2320, and element side surface 2315,and transition region 2325 may extend generally parallel to chamfer 2324from superabrasive face 2320 to element side surface 2315.

FIG. 36 shows an exemplary superabrasive element 2410 comprising asuperabrasive table 2414 having a rear surface 2418, a superabrasiveface 2420, and an element side surface 2415. Superabrasive table 2414may also form a chamfer 2424 and one or more cutting edges, such as edge2427 and edge 2428, adjacent to chamfer 2424. Element side surface 2415of superabrasive element 2410 may radially surround a central axis 2429of superabrasive element 2410.

Superabrasive element 2410 may include a first volume 2421 comprising aninterstitial material and a second volume 2423 having a lowerconcentration of the interstitial material than first volume 2421.Portions of superabrasive table 2414, such as second volume 2423, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 2425 may extend between first volume 2421 and second volume 2423so as to border at least a portion of first volume 2421 and secondvolume 2423. Transition region 2425 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 2421 and an amount of the interstitial materialin second volume 2423. In other embodiments, the boundary may be welldefined (i.e., transition region 2425 may be thin compared to a depth ofsecond volume 2423).

As shown in FIG. 36, second volume 2423 may be formed adjacent tochamfer 2424, superabrasive face 2420, and element side surface 2415,and transition region 2425 may extend from superabrasive face 2420 toelement side surface 2415, with a portion of transition region 2425extending generally parallel to chamfer 2424 and another portion oftransition region 2425 extending generally parallel to element sidesurface 2415.

FIG. 37 shows an exemplary superabrasive element 2510 comprising asuperabrasive table 2514 having a rear surface 2518, a superabrasiveface 2520, and an element side surface 2515. Superabrasive table 2514may also form a chamfer 2524 and one or more cutting edges, such as edge2527 and edge 2528, adjacent to chamfer 2524. Element side surface 2515of superabrasive element 2510 may radially surround a central axis 2529of superabrasive element 2510.

Superabrasive element 2510 may include a first volume 2521 comprising aninterstitial material and a second volume 2523 having a lowerconcentration of the interstitial material than first volume 2521.Portions of superabrasive table 2514, such as second volume 2523, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 2525 may extend between first volume 2521 and second volume 2523so as to border at least a portion of first volume 2521 and secondvolume 2523. Transition region 2525 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 2521 and an amount of the interstitial materialin second volume 2523. In other embodiments, the boundary may be welldefined (i.e., transition region 2525 may be thin compared to a depth ofsecond volume 2523).

As shown in FIG. 37, second volume 2523 may be formed adjacent tochamfer 2524 and element side surface 2515, and transition region 2525may extend from edge 2527 formed at the intersection of chamfer 2524 andsuperabrasive face 2520 to element side surface 2515, with a portion oftransition region 2525 extending generally parallel to element sidesurface 2515.

FIG. 38 shows an exemplary superabrasive element 2610 comprising asuperabrasive table 2614 having a rear surface 2618, a superabrasiveface 2620, and an element side surface 2615. Superabrasive table 2614may also form a chamfer 2624 and one or more cutting edges, such as edge2627 and edge 2628, adjacent to chamfer 2624. Element side surface 2615of superabrasive element 2610 may radially surround a central axis 2629of superabrasive element 2610.

Superabrasive element 2610 may include a first volume 2621 comprising aninterstitial material and a second volume 2623 having a lowerconcentration of the interstitial material than first volume 2621.Portions of superabrasive table 2614, such as second volume 2623, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 2625 may extend between first volume 2621 and second volume 2623so as to border at least a portion of first volume 2621 and secondvolume 2623. Transition region 2625 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 2621 and an amount of the interstitial materialin second volume 2623. In other embodiments, the boundary may be welldefined (i.e., transition region 2625 may be thin compared to a depth ofsecond volume 2623).

As shown in FIG. 38, second volume 2623 may be formed adjacent tochamfer 2624 and transition region 2625 may extend from edge 2627 toedge 2628, which are each adjacent to chamfer 2624. Transition region2625 may extend along any suitable profile between edge 2627 and edge2628, without limitation. According to some embodiments, transitionregion 2625 may comprise an angular profile, as illustrated in FIG. 38.A thickness or depth of second volume 2623, as measured perpendicular toa surface of chamfer 2624, may be maximum generally near the center ofchamfer 2624.

FIG. 39 shows an exemplary superabrasive element 2710 comprising asuperabrasive table 2714 having a rear surface 2718, a superabrasiveface 2720, and an element side surface 2715. Superabrasive table 2714may also form a chamfer 2724 and one or more cutting edges, such as edge2727 and edge 2728, adjacent to chamfer 2724. Element side surface 2715of superabrasive element 2710 may radially surround a central axis 2729of superabrasive element 2710.

Superabrasive element 2710 may include a first volume 2721 comprising aninterstitial material and a second volume 2723 having a lowerconcentration of the interstitial material than first volume 2721.Portions of superabrasive table 2714, such as second volume 2723, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 2725 may extend between first volume 2721 and second volume 2723so as to border at least a portion of first volume 2721 and secondvolume 2723. Transition region 2725 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 2721 and an amount of the interstitial materialin second volume 2723. In other embodiments, the boundary may be welldefined (i.e., transition region 2725 may be thin compared to a depth ofsecond volume 2723).

As shown in FIG. 39, second volume 2723 may be formed adjacent tochamfer 2724 and transition region 2725 may extend from edge 2727 toedge 2728, which are each adjacent to chamfer 2724. Transition region2725 may extend along any suitable profile between edge 2727 and edge2728, without limitation. According to some embodiments, transitionregion 2725 may comprise an arcuate profile, as illustrated in FIG. 39.A thickness or depth of second volume 2723, as measured perpendicular toa surface of chamfer 2724, may be maximum generally near the center ofchamfer 2724.

FIG. 40A shows an exemplary superabrasive element 2810 comprising asuperabrasive table 2814 having a rear surface 2818, a superabrasiveface 2820, and an element side surface 2815. Superabrasive table 2814may also form a chamfer 2824 and one or more cutting edges, such as edge2827 and edge 2828, adjacent to chamfer 2824. Element side surface 2815of superabrasive element 2810 may radially surround a central axis 2829of superabrasive element 2810.

Superabrasive element 2810 may include a first volume 2821 comprising aninterstitial material and a second volume 2823 having a lowerconcentration of the interstitial material than first volume 2821.Portions of superabrasive table 2814, such as second volume 2823, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 2825 may extend between first volume 2821 and second volume 2823so as to border at least a portion of first volume 2821 and secondvolume 2823. Transition region 2825 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 2821 and an amount of the interstitial materialin second volume 2823. In other embodiments, the boundary may be welldefined (i.e., transition region 2825 may be thin compared to a depth ofsecond volume 2823).

As shown in FIG. 40A, second volume 2823 may be formed adjacent tochamfer 2824 and transition region 2825 may extend from superabrasiveface 2820 to element side surface 2815. Transition region 2825 mayextend along any suitable profile between superabrasive face 2820 andelement side surface 2815, without limitation. Transition region 2825may comprise, for example, a profile that generally slopes betweensuperabrasive face 2820 and element side surface 2815. For example,transition region 2825 may extend from a region of element side surface2815 near edge 2828 to a region of superabrasive face 2820 disposedapart from edge 2827. According to some embodiments, as shown in FIG.40A, the generally annular-shaped second volume 2823 may comprise agenerally ring-shaped volume that is not perfectly symmetric but isirregular in one or more dimensions. For example, second volume 2823 mayvary in leach depth and/or profile shape, as defined by transitionregion 2825, at different peripheral regions about central axis 2829.

FIG. 40B shows an exemplary superabrasive element 2910 comprising asuperabrasive table 2914 having a rear surface 2918, a superabrasiveface 2920, and an element side surface 2915. Superabrasive table 2914may also form a chamfer 2924 and one or more cutting edges, such as edge2927 and edge 2928, adjacent to chamfer 2924. Element side surface 2915of superabrasive element 2910 may radially surround a central axis 2929of superabrasive element 2910.

Superabrasive element 2910 may include a first volume 2921 comprising aninterstitial material and a second volume 2923 having a lowerconcentration of the interstitial material than first volume 2921.Portions of superabrasive table 2914, such as second volume 2923, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 2925 may extend between first volume 2921 and second volume 2923so as to border at least a portion of first volume 2921 and secondvolume 2923. Transition region 2925 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 2921 and an amount of the interstitial materialin second volume 2923. In other embodiments, the boundary may be welldefined (i.e., transition region 2925 may be thin compared to a depth ofsecond volume 2923).

As shown in FIG. 40B, second volume 2923 may be formed adjacent tochamfer 2924 and transition region 2925 may extend from superabrasiveface 2920 to element side surface 2915. Transition region 2925 mayextend along any suitable profile between superabrasive face 2920 andelement side surface 2915, without limitation. Transition region 2925may comprise, for example, a profile that generally slopes betweensuperabrasive face 2920 and element side surface 2915. For example,transition region 2925 may extend from a region of element side surface2915 near edge 2928 to a region of superabrasive face 2920 disposedapart from edge 2927. According to some embodiments, as shown in FIG.40B, the generally annular-shaped second volume 2923 may comprise agenerally ring-shaped volume that is not perfectly symmetric but isirregular in one or more dimensions. For example, second volume 2923 mayvary in leach depth and/or profile shape, as defined by transitionregion 2925, at different peripheral regions about central axis 2929.

FIG. 41A shows an exemplary superabrasive element 3010 comprising asuperabrasive table 3014 having a rear surface 3018, a superabrasiveface 3020, and an element side surface 3015. Superabrasive table 3014may also form a chamfer 3024 and one or more cutting edges, such as edge3027 and edge 3028, adjacent to chamfer 3024. Element side surface 3015of superabrasive element 3010 may radially surround a central axis 3029of superabrasive element 3010.

Superabrasive element 3010 may include a first volume 3021 comprising aninterstitial material and a second volume 3023 having a lowerconcentration of the interstitial material than first volume 3021.Portions of superabrasive table 3014, such as second volume 3023, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 3025 may extend between first volume 3021 and second volume 3023so as to border at least a portion of first volume 3021 and secondvolume 3023. Transition region 3025 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 3021 and an amount of the interstitial materialin second volume 3023. In other embodiments, the boundary may be welldefined (i.e., transition region 3025 may be thin compared to a depth ofsecond volume 3023).

As shown in FIG. 41A, second volume 3023 may be formed adjacent tochamfer 3024, superabrasive face 3020, and element side surface 3015,and transition region 3025 may extend from superabrasive face 3020 torear surface 3018 (or to an interface between superabrasive table 3014and an adjacent substrate), with transition region 3025 extendinggenerally parallel to element side surface 3015.

FIG. 41B shows an exemplary superabrasive element 3110 comprising asuperabrasive table 3114 having a rear surface 3118, a superabrasiveface 3120, and an element side surface 3115. Superabrasive table 3114may also form a chamfer 3124 and one or more cutting edges, such as edge3127 and edge 3128, adjacent to chamfer 3124. Element side surface 3115of superabrasive element 3110 may radially surround a central axis 3129of superabrasive element 3110.

Superabrasive element 3110 may include a first volume 3121 comprising aninterstitial material and a second volume 3123 having a lowerconcentration of the interstitial material than first volume 3121.Portions of superabrasive table 3114, such as second volume 3123, may beleached or otherwise processed to remove interstitial materials, such asa metal-solvent catalyst, from the interstitial regions. A transitionregion 3125 may extend between first volume 3121 and second volume 3123so as to border at least a portion of first volume 3121 and secondvolume 3123. Transition region 3125 may include amounts of aninterstitial material varying between an amount of the interstitialmaterial in first volume 3121 and an amount of the interstitial materialin second volume 3123. In other embodiments, the boundary may be welldefined (i.e., transition region 3125 may be thin compared to a depth ofsecond volume 3123).

As shown in FIG. 41B, second volume 3123 may be formed adjacent tochamfer 3124, superabrasive face 3120, and element side surface 3115,and transition region 3125 may extend from superabrasive face 3120 torear surface 3118 (or to an interface between superabrasive table 3114and an adjacent substrate).

FIG. 42 is a perspective view of an exemplary drill bit 80 according toat least one embodiment. Drill bit 80 may represent any type or form ofearth-boring or drilling tool, including, for example, a rotary drillbit. As illustrated in FIG. 42, drill bit 80 may comprise a bit body 81having a longitudinal axis 84. Bit body 81 may define a leading endstructure for drilling into a subterranean formation by rotating bitbody 81 about longitudinal axis 84 and applying weight to bit body 81.Bit body 81 may include radially and longitudinally extending blades 79with leading faces 82 and a threaded pin connection 83 for connectingbit body 81 to a drill string.

At least one superabrasive element according to any of the embodimentsdisclosed herein may be coupled to bit body 81. For example, as shown inFIG. 42, a plurality of superabrasive elements 10 may be coupled toblades 79. Drill bit 80 may utilize any of the disclosed superabrasiveelements 10 as cutting elements. Circumferentially adjacent blades 79may define so-called junk slots 85 therebetween. Junk slots 85 may beconfigured to channel debris, such as rock or formation cuttings, awayfrom superabrasive elements 10 during drilling. Drill bit 80 may alsoinclude a plurality of nozzle cavities 86 for communicating drillingfluid from the interior of drill bit 80 to superabrasive elements 10.

FIG. 42 depicts an example of a drill bit 80 that employs at least onecutting element 10. Drill bit 80 may represent any number ofearth-boring tools or drilling tools, including, for example, core bits,roller-cone bits, fixed-cutter bits, eccentric bits, bicenter bits,reamers, reamer wings, and/or any other downhole tools comprisingsuperabrasive cutting elements and/or discs, without limitation.Superabrasive elements 10 disclosed herein may also be utilized inapplications other than cutting technology. For example, embodiments ofsuperabrasive elements 10 disclosed herein may also form all or part ofheat sinks, wire dies, bearing elements, cutting elements, cuttinginserts (e.g., on a roller cone type drill bit), machining inserts, orany other article of manufacture, as known in the art. According to someexamples, superabrasive elements 10, as disclosed herein, may beemployed in medical device applications, including, without limitation,hip joints, back joints, or any other suitable medical joints. Thus,superabrasive elements 10, as disclosed herein, may be employed in anysuitable article of manufacture. Other examples of articles ofmanufacture that may incorporate superabrasive elements as disclosedherein may be found in U.S. Pat. Nos. 4,811,801; 4,268,276; 4,468,138;4,738,322; 4,913,247; 5,016,718; 5,092,687; 5,120,327; 5,135,061;5,154,245; 5,460,233; 5,544,713; and 6,793,681, the disclosure of eachof which is incorporated herein, in its entirety, by this reference.

In additional embodiments, a rotor and a stator, such as a rotor and astator used in a thrust bearing apparatus, may each include at least onesuperabrasive element according to the embodiments disclosed herein. Byway of example, U.S. Pat. Nos. 4,410,054; 4,560,014; 5,364,192;5,368,398; and 5,480,233, the disclosure of each of which isincorporated herein, in its entirety, by this reference, disclosesubterranean drilling systems that include bearing apparatuses utilizingsuperabrasive elements 10 as disclosed herein.

FIG. 43 is partial cross-sectional perspective view of an exemplarythrust-bearing apparatus 87 according to at least one embodiment.Thrust-bearing apparatus 87 may utilize any of the disclosedsuperabrasive elements 10 as bearing elements. Thrust-bearing apparatus87 may also include bearing assemblies 88A and 88B. Each of bearingassembly 88A and 88B may include a support ring 89 fabricated from amaterial, such as steel, stainless steel, or any other suitablematerial, without limitation.

Each support ring 89 may include a plurality of recesses 90 configuredto receive corresponding superabrasive elements 10. Each superabrasiveelement 10 may be mounted to a corresponding support ring 89 within acorresponding recess 90 by brazing, welding, press-fitting, usingfasteners, or any another suitable mounting technique, withoutlimitation. In at least one embodiment, one or more of superabrasiveelements 10 may be configured according to any of the superabrasiveelement embodiments described herein. For example, each superabrasiveelement 10 may include a substrate 12 and a superabrasive table 14comprising a PCD material. Each superabrasive table 14 may form asuperabrasive face 20 that is utilized as a bearing surface.

Superabrasive faces 20 of bearing assembly 88A may bear against opposingsuperabrasive faces 20 of bearing assembly 88B in thrust-bearingapparatus 87, as illustrated in FIG. 43. For example, bearing assembly88A of thrust-bearing apparatus 87 may be termed a “rotor.” The rotormay be operably coupled to a rotational shaft. Bearing assembly 88B ofthrust-bearing apparatus 87 may be held substantially stationaryrelative to the bearing assembly 88A and may be termed a “stator.”

FIG. 44 is a perspective view of a radial bearing apparatus 91 accordingto another embodiment. Radial bearing apparatus 91 may utilize any ofthe disclosed superabrasive element embodiments as bearing elements 10Aand 10B. Radial bearing apparatus 91 may include an inner race 92Apositioned generally within an outer race 92B. Inner race 92A mayinclude a plurality of bearing elements 10A affixed thereto, and outerrace 92B may include a plurality of corresponding bearing elements 10Baffixed thereto. One or more of bearing elements 10A and 10B may beconfigured in accordance with any of the superabrasive elementembodiments disclosed herein.

Inner race 92A may be positioned generally within outer race 92B. Thus,inner race 92A and outer race 92B may be configured such that bearingsurfaces 20A defined by bearing elements 10A and bearing surfaces 20Bdefined by bearing elements 10B may at least partially contact oneanother and move relative to one another as inner race 92A and outerrace 92B rotate relative to each other. According to variousembodiments, thrust-bearing apparatus 87 and/or radial bearing apparatus91 may be incorporated into a subterranean drilling system.

FIG. 45 is a partial cross-sectional perspective view of an exemplarysubterranean drilling system 93 that includes a thrust-bearing apparatus87, as shown in FIG. 43, according to at least one embodiment. Thesubterranean drilling system 93 may include a housing 94 enclosing adownhole drilling motor 95 (i.e., a motor, turbine, or any othersuitable device capable of rotating an output shaft, without limitation)that is operably connected to an output shaft 96.

The thrust-bearing apparatus 87 shown in FIG. 43 may be operably coupledto downhole drilling motor 95. A rotary drill bit 97, such as a rotarydrill bit configured to engage a subterranean formation and drill aborehole, may be connected to output shaft 96. As illustrated in FIG.45, rotary drill bit 97 may be a roller cone bit comprising a pluralityof roller cones 98. According to additional embodiments, rotary drillbit 97 may comprise any suitable type of rotary drill bit, such as, forexample, a so-called fixed-cutter drill bit. As a borehole is drilledusing rotary drill bit 97, pipe sections may be connected tosubterranean drilling system 93 to form a drill string capable ofprogressively drilling the borehole to a greater depth within asubterranean formation.

A thrust-bearing assembly 88A in thrust-bearing apparatus 87 may beconfigured as a rotor that is attached to output shaft 96 and athrust-bearing assembly 88B in thrust-bearing apparatus 87 may beconfigured as a stator. During a drilling operation using subterraneandrilling system 93, the rotor may rotate in conjunction with outputshaft 96 and the stator may remain substantially stationary relative tothe rotor.

According to various embodiments, drilling fluid may be circulatedthrough downhole drilling motor 95 to generate torque and effectrotation of output shaft 96 and rotary drill bit 97 attached thereto sothat a borehole may be drilled. A portion of the drilling fluid may alsobe used to lubricate opposing bearing surfaces of superabrasive elements10 on thrust-bearing assemblies 88A and 88B.

FIG. 46 illustrates an exemplary method 3000 for processing apolycrystalline diamond element according to at least one embodiment. Asshown in FIG. 46, at least a portion of a polycrystalline diamondmaterial may be exposed to a processing solution, the polycrystallinethe polycrystalline diamond material comprising a metallic materialdisposed in interstitial spaces defined within the polycrystallinediamond material (process 3202). In some embodiments, for example, asuperabrasive element 10 comprising a superabrasive table 14 and asubstrate 12 may be disposed in a protective leaching cup 30 such thatthe protective leaching cup surrounds substrate 12 and/or at least aportion of superabrasive table 14. Superabrasive element 10 andprotective leaching cup 30 may be disposed in a cavity 76 of aprocessing vessel 70 such that a processing solution 72 contacts atleast a portion of superabrasive element 10 as illustrated in FIG. 9C.

An electrode may be exposed to the processing solution (process 3204).For example, as shown in FIG. 9C, an electrode 40 may be disposed inprocessing vessel 70 such that electrode 40 and superabrasive element 10surrounded by protective leaching cup 30 are at least partiallysubmerged in processing solution 72. Electrode 40 may be exposed toprocessing solution 72 such that processing solution 72 contacts atleast a portion of electrode 40.

A first charge may be applied to the polycrystalline diamond material(process 3206). For example, as shown in FIG. 9C, a charge may beapplied to superabrasive element 10 through an electrical conductor 44.In some embodiments, a positive charge may be applied to at least aportion of substrate 12 (e.g., rear surface 18) of superabrasive element10 through electrical conductor 44. In at least one embodiment,electrical conductor 44 may be electrically connected to substrate 12 byan electrode electrically connected to (e.g., positioned abutting)substrate 12. In some embodiments, electrical conductor 44 may bedirectly connected to superabrasive table 14 by an electrodeelectrically connected to (e.g., positioned abutting) superabrasivetable 14.

A second charge may be applied to the electrode (process 3208). Forexample, as shown in FIG. 9C, a charge may be applied to electrode 40through an electrical conductor 42. In some embodiments, an oppositecharge (e.g., a negative charge) may be applied to electrode 40 throughelectrical conductor 42.

FIG. 47 illustrates an exemplary method 3300 for processing apolycrystalline diamond element according to at least one embodiment. Asshown in FIG. 47, a superabrasive element may be provided, thesuperabrasive element comprising a substrate and a polycrystallinediamond table bonded to the substrate, the polycrystalline diamond tablecomprising a metallic material disposed in interstitial spaces definedwithin the polycrystalline diamond table (process 3302). For example, asshown in FIGS. 1 and 2, a superabrasive element 10 comprising asubstrate 12 bonded to a superabrasive table 14 may be provided.Superabrasive table 14 may comprise a polycrystalline diamond table withmetal-solvent catalyst and/or other materials (e.g. interstitialmaterial 39) disposed in interstitial spaces (e.g. interstitial regions36) defined within the polycrystalline diamond table, as illustrated inFIGS. 5-6.

At least a portion of the polycrystalline diamond table may be exposedto a processing solution (process 3304). In some embodiments, forexample, a superabrasive element 10 may be disposed in a protectiveleaching cup 30 such that the protective leaching cup surroundssubstrate 12 and/or at least a portion of superabrasive table 14.Superabrasive element 10 and protective leaching cup 30 may be disposedin a cavity 76 of a processing vessel 70 such that a processing solution72 contacts at least a portion of superabrasive element 10 asillustrated in FIG. 9C.

An electrode may be exposed to the processing solution (process 3306).For example, as shown in FIG. 9C, an electrode 40 may be disposed inprocessing vessel 70 such that electrode 40 and superabrasive element 10surrounded by protective leaching cup 30 are at least partiallysubmerged in processing solution 72. Electrode 40 may be exposed toprocessing solution 72 such that processing solution 72 contacts atleast a portion of electrode 40.

A first charge may be applied to the metallic material (process 3308).For example, as shown in FIG. 9C, a charge may be applied tosuperabrasive element 10 through an electrical conductor 44.

A second charge may be applied to the electrode (process 3310). Forexample, as shown in FIG. 9C, an opposite charge may be applied toelectrode 40 through an electrical conductor 42.

The following examples set forth various methods used to formsuperabrasive elements as disclosed herein. The following examplesprovide further detail in connection with the specific embodimentsdescribed above.

Example 1

Cutting elements, each comprising a PCD table attached to a tungstencarbide substrate, were formed by HPHT sintering diamond particles inthe presence of cobalt. The sintered-polycrystalline-diamond tablesincluded cobalt and tungsten within the interstitial regions between thebonded diamond grains.

The PCD tables were leached using an aqueous processing solution havinga molar concentration of 0.29 M citric acid. The processing solution forprocessing each cutting element contacted both the PCD table and acorresponding disk-shaped copper electrode disposed near the PCD table.A negative charge was applied to each electrode and a positive chargewas applied to the substrate of each cutting element such that a voltageof 0.8 V was generated in the processing solution. The PCD tables wereleached at a temperature of approximately 75° C. and atmosphericpressure for between 24 and 168 hours. Following leaching, leacheddepths of the PCD tables were determined for various portions of the PCDtables, including leached depths measured from the cutting faces, sidesurfaces, and chamfered cutting edges of the PCD tables, and the leacheddepths were averaged.

Following 24 hours of leaching, a first PCD table included a leacheddepth of approximately 167 μm.

Following 72 hours of leaching, a second PCD table included a leacheddepth of approximately 308 μm.

Following 168 hours of leaching, a third PCD table included a leacheddepth of approximately 611 μm.

Example 2

Cutting elements, each comprising a PCD table attached to a tungstencarbide substrate, were formed by HPHT sintering diamond particles inthe presence of cobalt. The sintered-polycrystalline-diamond tablesincluded cobalt and tungsten within the interstitial regions between thebonded diamond grains.

The PCD tables were leached using an aqueous processing solution havinga citrate buffer comprising a molar concentration of 0.24 M sodiumcitrate and 0.05 M citric acid and having a pH of 6.5. The processingsolution for processing each cutting element contacted both the PCDtable and a corresponding disk-shaped copper electrode disposed near thePCD table. A negative charge was applied to each electrode and apositive charge was applied to the substrate of each cutting elementsuch that a voltage of 0.8 V was generated in the processing solution.The PCD tables were leached at a temperature of approximately 75° C. andatmospheric pressure for between 24 and 72 hours. Following leaching,leached depths of the PCD tables were determined for various portions ofthe PCD tables, including leached depths measured from the cuttingfaces, side surfaces, and chamfered cutting edges of the PCD tables, andthe leached depths were averaged.

Following 24 hours of leaching, a first PCD table included a leacheddepth of approximately 120 μm.

Following 72 hours of leaching, a second PCD table included a leacheddepth of approximately 250 μm.

Example 3

Cutting elements, each comprising a PCD table attached to a tungstencarbide substrate, were formed by HPHT sintering diamond particles inthe presence of cobalt. The sintered-polycrystalline-diamond tablesincluded cobalt and tungsten within the interstitial regions between thebonded diamond grains.

The PCD tables were each leached in one of a plurality of aqueousprocessing solutions having a molar concentration of 0.29 M citric acidand various concentrations of cobalt chloride. The processing solutionsfor processing each cutting element contacted both the PCD table and acorresponding disk-shaped copper electrode disposed near the PCD table.A negative charge was applied to each electrode and a positive chargewas applied to the substrate of each cutting element such that a voltageof 0.8 V was generated in the processing solution. The PCD tables wereleached at a temperature of approximately 75° C. and atmosphericpressure for 72 hours. Following leaching, leached depths of the PCDtables were determined for various portions of the PCD tables, includingleached depths measured from the cutting faces, side surfaces, andchamfered cutting edges of the PCD tables, and the leached depths wereaveraged.

Following leaching in a processing solution containing no cobaltchloride, a first PCD table included a leached depth of approximately188 μm.

Following leaching in a processing solution having a molar concentrationof 0.05 M cobalt chloride, a first PCD table included a leached depth ofapproximately 219 μm.

Following leaching in a processing solution having a molar concentrationof 0.1 M cobalt chloride, a first PCD table included a leached depth ofapproximately 233 μm.

The preceding description has been provided to enable others skilled inthe art to best utilize various aspects of the exemplary embodimentsdescribed herein. This exemplary description is not intended to beexhaustive or to be limited to any precise form disclosed. Manymodifications and variations are possible without departing from thespirit and scope of the instant disclosure. It is desired that theembodiments described herein be considered in all respects illustrativeand not restrictive and that reference be made to the appended claimsand their equivalents for determining the scope of the instantdisclosure.

Unless otherwise noted, the terms “a” or “an,” as used in thespecification and claims, are to be construed as meaning “at least oneof” In addition, for ease of use, the words “including” and “having,” asused in the specification and claims, are interchangeable with and havethe same meaning as the word “comprising.”

What is claimed is:
 1. A superabrasive element produced by a processcomprising: producing a leached volume in a polycrystalline diamondtable of the superabrasive element, the polycrystalline diamond tablecomprising a metallic material disposed in interstitial spaces definedwithin the polycrystalline diamond table, the producing the leachedvolume comprising: exposing at least a portion of the polycrystallinediamond table to a processing solution; exposing an electrode to theprocessing solution; applying a charge to the electrode to generate avoltage between the polycrystalline diamond table and the electrode viathe processing solution; leaching the metallic material from a portionof the polycrystalline diamond table to a first depth relative to asuperabrasive face of the superabrasive element; and leaching themetallic material from an external side region of the polycrystallinediamond table to a second depth relative to the superabrasive face ofthe superabrasive element, the second depth being greater than the firstdepth.
 2. The superabrasive element of claim 1, the process furthercomprising positioning the electrode relatively closer in proximity tothe external side region of the superabrasive element than a centralportion of the superabrasive face of the superabrasive element.
 3. Thesuperabrasive element of claim 2, wherein the electrode comprises a ringshape.
 4. The superabrasive element of claim 1, the process furthercomprising surrounding at least a portion of the superabrasive elementwith a protective layer.
 5. The superabrasive element of claim 4,further comprising a substrate attached to the polycrystalline diamondtable, the process further comprising surrounding at least the substratewith the protective layer.
 6. The superabrasive element of claim 4, theprocess further comprising contacting a portion of the polycrystallinediamond table with the protective layer.
 7. The superabrasive element ofclaim 6, the process further comprising contacting a portion of theexternal side region of the polycrystalline diamond table with theprotective layer to form a seal between the protective layer and thesuperabrasive element.
 8. The superabrasive element of claim 1, theprocess further comprising disposing the superabrasive element in aprocessing vessel.
 9. The superabrasive element of claim 1, the processfurther comprising disposing the electrode near at least one of thesuperabrasive face and the external side region, wherein the electrodedoes not directly contact the superabrasive face or the external sideregion.
 10. The superabrasive element of claim 9, the process furthercomprising disposing the electrode in closer proximity to the externalside region than to a central portion of the superabrasive face.
 11. Thesuperabrasive element of claim 1, the process further comprisingleaching the metallic material from the external side region of thepolycrystalline diamond table to a third depth relative to a sidesurface of the superabrasive element, the third depth being greater thanthe first depth.
 12. The superabrasive element of claim 1, the processfurther comprising selecting the processing solution to exhibit a pHbelow approximately
 1. 13. A superabrasive element produced by a processcomprising: providing a superabrasive element comprising apolycrystalline diamond table that comprises a metallic materialdisposed in interstitial spaces defined within the polycrystallinediamond table, the polycrystalline diamond table comprising: asuperabrasive face; and a superabrasive side surface extending around anouter periphery of the superabrasive face; surrounding at least aportion of the superabrasive element with a protective layer; contactinga portion of the superabrasive side surface of the polycrystallinediamond table with the protective layer; leaching the metallic materialfrom at least a volume of the polycrystalline diamond table to produce aleached volume in the polycrystalline diamond table by: exposing atleast a portion of the polycrystalline diamond table to a processingsolution; exposing an electrode to the processing solution; applying acharge to the electrode such that a voltage is generated between thepolycrystalline diamond table and the electrode and the voltage isapplied to the processing solution; leaching a central portion of thesuperabrasive face of the superabrasive element; and leaching a regionadjacent to the superabrasive side surface of the superabrasive element;and removing the protective layer from the superabrasive element. 14.The superabrasive element of claim 13, the process further comprisingsubstantially preventing or delaying the processing solution fromcontacting the at least a portion of the superabrasive element with theprotective layer comprising a protective masking layer.
 15. Thesuperabrasive element of claim 13, the process further comprisingselecting the protective layer to comprise a protective leaching cupthat is partially or fully impermeable to the processing solution. 16.The superabrasive element of claim 15, the process further comprisingforming a seal between the protective leaching cup and the superabrasiveelement.
 17. The superabrasive element of claim 15, wherein theprotective leaching cup is formed with an opening enabling an electricalconductor to contact a surface of a substrate of the superabrasiveelement that carries the polycrystalline diamond table.
 18. Thesuperabrasive element of claim 13, the process further comprisingpositioning the electrode relatively closer to the superabrasive sidesurface of the superabrasive element.
 19. A superabrasive elementproduced by a process comprising: leaching a metallic material from atleast a volume of a polycrystalline diamond table of the superabrasiveelement to produce a leached volume in the polycrystalline diamondtable, the polycrystalline diamond table comprising the metallicmaterial disposed in interstitial spaces defined within thepolycrystalline diamond table, the leaching comprising: exposing atleast a portion of the polycrystalline diamond table to a processingsolution exhibiting a pH below approximately 1; applying a charge to anelectrode in communication with the processing solution; generating avoltage between the polycrystalline diamond table and the electrode; andleaching a region of the polycrystalline diamond table to a depthunderlying a superabrasive face of the superabrasive element.
 20. Thesuperabrasive element of claim 19, the process further comprising:disposing the polycrystalline diamond table on a substrate; covering atleast a portion of the superabrasive element with a protective leachingcup; and extending an electrical conductor through the protectiveleaching cup to contact a surface of the substrate.